Protein Yoghurt Plum Cake with Sourdough

Ditch the dry, chalky protein cake! This Protein Yoghurt Plum Cake with Sourdough is a deliciously tender, moist, and buttery answer to your sweet cravings. I combine the incredible tang and texture-improving properties of sourdough discard, moisture-rich Greek yogurt, and the irresistible nutty depth of browned butter. Topped with juicy seasonal plums, this recipe sneaks in a boost of protein, making this indulgent-tasting cake a smarter treat that will surprise your guests.

 

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• Why You’ll Love This
• The Ingredients
• Substitutions
• Equipment Used
• How to Make this
• How To Store
• FAQ
• Other Recipes You Might Enjoy

Why You’ll Love This 

TL;DR

• Tender & Moist: The perfect balance of sourdough discard, Greek yogurt, and real butter counters the drying effect of protein powder.
• Healthier Dessert: Enjoy a rich, buttery cake with over 7g protein and around 300 calories per generous slice.
• Simple & Seasonal: Made in one bowl and a saucepan, it’s quick enough for a weekday and perfect for seasonal plums (or other stone fruit).
• Flavor Boosts: Features the irresistible nutty notes of browned butter and the complex tang of sourdough discard.
• Use Up Discard: A delicious way to keep your sourdough starter discard from going to waste.

Tender, Moist Cake With Protein

Have you ever had protein cake that was dry, too chewy or just…didn’t taste right and wondered if there are recipes that solve all those issues?
This Yoghurt Plum cake will surprise you in all the right ways and make you love protein baking, I promise.
The combination of ingredients makes sure there is a balance between the drying effect of protein powder and the tenderizing properties of the sourdough discard plus the incredible moisture Greek yogurt brings to the batter, all topped by juicy seasonal plums.

Serve To Guests, No One Will Know It’s Healthier

Because I’m using real butter and sugar instead of replacing them with sweetener and other “healthy” ingredients, this cake tastes like cake should: Buttery, sweet and indulgent.
Yet by using 0% fat Greek yoghurt, that tastes virtually identical in cake to the full fat version and replacing just a part of the sugar in the original with the sweetener that is included in vanilla protein powder, you get cake that comes with just over 300 calories per very generous slice (I calculated with 8 very generous slices here) and has more than 7g protein per portion, making it a great low calorie and higher protein option for dessert. And the Plums are of course one of your 5 a day.

Easy And Seasonal

I do love plum cake, as you can see in my German Plum Streusel Cake which is firm part of my fall ritual.
But this year I wanted to add a cake that is even easier to make whenever I can get my hands on lovely fresh fruits.
It uses just one bowl and a saucepan, so you can whip up this easy plum cake even midweek or for surprise guests.
While I adore plums, you can use any stone fruit that is in season. Cherries would be amazing or try peaches!

Use Up Sourdough Discard

The sourdough seems like a bit of a sidenote in many baking recipes, as it doesn’t get to slow ferment overnight and doesn’t add much to the rise. But apart from getting to use up your discard, it counters the drying effect protein powder can have very effectively and its tang gives this moist yoghurt cake even more depth of flavor.

Nutty Browned Butter

Now here is another great point: Because sourdough discard is made up of half water, a slight reduction of liquids from the original recipe was necessary to make this protein cake work. And what better way to do this than by browning the butter?
This not only evaporates a good part of the water content in butter but also adds irresistible nutty notes to the cake that you’ll taste in every single bite.

Ingredient Notes

As usual just a few notes on key ingredients. The complete list with amounts is in the recipe card below.

• Plums – I used relatively large plums and cut them into 8 pieces each. If you have smaller ones or damsons, halve them. I found this cake works well with both lovely ripe fruits and slightly under ripe ones, as the baking reduces all of them to a lovely sweet jammy texture.

Batter

• All-Purpose Flour – This is the best flour to use for tender cake that just melts in your mouth.
• Butter – I always use unsalted, so I can control any salt that goes into my recipes. And, because I live in Ireland, Irish butter is of course what I use. It does make a big difference in flavor, so try to get the best butter you can.
• Protein Powder – MyProtein Whey vanilla is what I use. Any nice tasting and non-chalky whey protein will work here. As for the ratio: In any batter recipes I found I can safely replace about a third of the original recipes’ flour content with protein powder without a drying effect. At least when used in conjunction with sourdough.
• Greek Yogurt– I almost exclusively work with 0% fat Greek yogurt, as I feel the flavor is lovely, yet it saves me a good few calories. Frankly, yoghurt is the only product I feel I can use in a low-fat version without making any frustrating compromises. Do use unflavored here, as any fruity ones will have a ton of added sugar, messing with the cakes flavor. Use it at room temperature for the best incorporation into the batter.
• Sourdough Discard – You can use relatively fresh discard here or active starter. Any discard up to roughly 5 days since the last feeding will be lovely. After that it might get a little too tangy, which you could balance with a teaspoon or two of added sugar.
• Eggs – You’ll notice that I’m using 1 whole egg and one egg yolk. This is to make up for the remaining water content from the sourdough discard. Taking out one egg white and browning the butter gave me the exact amount I needed, since this batter doesn’t include any milk or water that would be simple to take out.

substitutions

• Plums – Any stone fruit like peaches, apricots or cherries will be wonderful in this cake. You could even make it with apples or pears in fall. Or a wild mix of different fruits.

Batter

• Butter – If you’d prefer to make a vegan version of this cake, you could use olive oil instead, bringing this closer to the original Italian “Torta di Susine” https://emmaduckworthbakes.com/yogurt-plum-cake/. Or use vegan butter and brown it.
• Eggs – For a vegan version replace the egg by using 40g more flour and add 50ml plant based milk. This measurement is calculated from the instructions in one of my favorite books on baking “The Elements of Baking”- If you bake anything “free from” on a regular basis, you definitely want to get this.
• Flour – To make this gluten-free, use a gluten free flour mix. If yours doesn’t contain any xanthan gum, add 1/8 tsp and about 1 tbsp less flour. You could also swap 1/3 of the AP flour for fine whole wheat for a lovely nutty flavor and a bit more fiber.
• Protein Powder – If you want to use a vegan protein powder, I would strongly recommend trying to get your hands on spent barley and rice protein. It acts similar to whey in baking, as I found in my tests for easy sourdough protein bread, but needs a little less liquid.
• I haven’t tried it in this cake, but theoretically, using the same amount of protein powder, but about 2 tbsp less yoghurt should work.
• Greek Yoghurt – Vegan will work here. Ideally low fat, but full fat is ok if you can’t find it.
• Sourdough Discard – If you’d like to make this cake without sourdough discard, you can reverse engineer it by using 2 whole eggs and skipping the butter browning step. However, because of the effect of the sourdough countering the protein powder dryness, it might not be as tender.

Equipment Used

• Saucepan – I used a saucepan to brown the butter, reducing its water content.
• Stand Mixer – I felt very lazy when making this cake, so I whipped it up in my stand mixer. You can absolutely just use a hand mixer or a whisk/spoon, a bowl and some elbow grease. Mine is a KitchenAid because I just adore the Pistachio color that goes perfectly with my kitchen design and it has a glass bowl, making it perfect for filming.
• Springform – I found a springform to be perfect for this cake. Its removable sides make it easy to unmold this moist, tender cake without disturbing the fruit topping or the delicate structure. Mine is from KitchenAid and has survived a few years now looking like new, despite regular use, while other brands fell apart after just a few bakes.

Saucepan

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KitchenAid

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springform

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How to Make this

Preheat your oven to 350°F/175°C

Prepare your springform by lining the bottom with baking parchment and greasing the sides with butter.

Brown The Butter

Get your mixing bowl ready and (if you are in a hurry) another, slightly bigger bowl that will fit your mixing bowl so it just touches the water, with cold water and ice.
I used metal for the bowl going into the ice bath, as it cools down faster than glass and isn’t sensitive to rapid temperature changes.

Before you do anything else, start by browning your butter in a saucepan.
To do this, melt the butter on medium/high heat until it bubbles, then reduce the heat to medium/low and stir the melted butter until the big bubbles transform in a fine foam.
This means the water has evaporated and your butter now starts to brown.
Watch it like a hawk, as it can burn in a heartbeat and keep stirring, so nothing sticks to the bottom of the pot.

Allow it to cook until it smells nutty and has deeply golden brown specks.

Take off the heat immediately and pour into your cake bowl, to avoid burning from the remaining heat of the pan.

Method 1: Passive cooling in the fridge (slow)

Now you can either allow it to cool for about 15-20 minutes in the fridge, until the center of the butter is still liquid, but the outsides are firm.

Method 2: Ice bath (fast)

Or do what I did and whisk it over an ice bath until solidified but still smooth.
You’ll have to whisk continuously to incorporate the cold pieces, where the butter is touching your bowl sides back into the warm parts, until you have a really smooth butter.

Take it out of the ice bath a little before it has reached the perfect creamy texture, as the cold bowl will keep firming it up.

Why bother with this step? Because melted butter leads to a completely different texture and possibly greasy cake instead of whipping up nicely with the sugar.

Now, this was the most “difficult” step of the whole process. Let’s get on with the even easier bits.

Whip The Butter With The Sugar

Add the sugar to the butter and whip until lighter and fluffy. This is easiest when using a stand mixer. But a whisk and a little workout will do too.

Add Eggs, Liquids and Protein Powder

Whisk in your eggs until fully incorporated, then the Greek yoghurt, Protein powder (so it can melt into the liquids), vanilla and, if using almond extract.

Fold In Flour And Sourdough Discard

Mix the baking powder and salt into your flour.

If you used a mixer, switch over at this point to a spatula.
Add both flour and sourdough discard to the batter and gently fold in until just combined.

Do not overmix! I did this step in my stand mixer once and it gave me a dense and gummy cake bottom instead of the fluffy and light, buttery sponge we are going for here. And that was with just a few seconds of mixing.

Prepare The Plums

Destone your plums, then slice them, depending on their size.
Mine where quite large, so I cut them into 6-8 pieces each.

Assemble Your Cake

Mix the cinnamon sugar.

Using a large cookie scoop or spoon, cover the bottom of your springform with about half of the batter.

Lay half of your plum slices over the batter. Try to get this relatively even.

Sprinkle half of the cinnamon sugar over them.

Top with the second half of the batter and finish with the second half of the plums. I put them in circles, for decoration, but scattering them over works too.

Now add the other half of the cinnamon sugar for a pretty and tasty cinnamon-sugar crust.
This will add sparkly bits, caramelise and give the whole plum cake a lovely warm cinnamon scent with incredible crispy edges.

Bake Your Protein Yoghurt Plum Cake with Sourdough

Bake for about 45-55 minutes until golden brown and a toothpick inserted into the center comes out clean.

I always turn my cakes about halfway through baking, to get an even browning, as most ovens I worked with brown slightly unevenly.

If your cake looks a little too dark before being cooked all the way through, cover with foil for the last 10 minutes. I love mine rather deep golden brown and a little crispy around the edges and didn’t need any foil. But tastes and ovens differ.

Enjoy with a cuppa and, if you like some whipped cream or more Greek yoghurt on top.
A scoop of vanilla ice cream would make this a particularly lovely treat for a warm late summer day on the porch.

This yoghurt plum cake is equally good warm or at room temperature.

How To Store

While this protein cake keeps in an airtight container for about a day or two, I usually store mine in the fridge or freezer, due to the high fruit and moisture content.

It also freezes incredibly well for about 6 months in a freezer proof container with lid. Usually I freeze in portions of 2 slices, so I can take one out and thaw when the mood strikes.

While it’s great at room temperature, I love this cake even more after heating it up in my air fryer for about 7 minutes at 350°F/175°C. It gets warm, which is nice, but even more importantly the edges crisp up just so, and the plums get even more jammy and sweet.
That way I can have my favorite late summer/fall dessert all year round, even without wasps trying to compete for it!

FAQ

Now I’d love to hear from you in the comments!

Have you tried this? Did you enjoy it?
What other recipes would you like to see?

And if you enjoyed this recipe, please consider rating, sharing, or leaving a comment – your feedback truly helps my blog grow!

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