Moist and fluffy Lemon Poppy Sourdough Zucchini Bread with Protein is my new favourite cake. Zingy lemon and crunchy poppy seeds are a classic, but when you mix it with shredded zucchini, you not only add extra veggies, but also low calorie moisture and these lovely green flecks in the batter, that make it super pretty. The sourdough adds a layer of tangy flavour and helps the batter bubble up even more. It also becomes bouncier and lighter. The protein powder means we can reduce the sugar and get more flavour, plus of course a nice hit of nutrition.
The unusual addition of thyme gives a tiny hint of herb flavour in the background, underlining the lemon notes inside the cake and in the glaze.
Topped with optional candied lemon slices, this is a pretty as it’s delicious.
Why You Want To Make This
During my weight loss journey, I was constantly on the hunt for recipes to satisfy my sweet tooth, that are lower in calories and have added benefits to fuel my body.
Cakes with sourdough, veggies and protein are very high on my list, as they hit all the boxes for me.
So, if you are on a similar journey, or simply are looking for ways to have your delicious protein cake and eat it, this is one for you.
You can serve this to friends and family and no one will ever suspect you smuggled something healthy into their diet, it tastes that good.
Eggs of course, as we want a light and fluffy cake. But we need only 2, since zucchini and protein powder take over the role of the third.
For the flour, I used 1 cup of white, then replaced the other cup you’d usually use with half a cup of fine whole wheat flour (you could use coarse, but it will change the light structure of the cake and don’t let it rise that well).
The remaining half cup is made up from the flour content in the sourdough discard (you can use either discard or active, whatever you have on hand. Since we don’t want much gluten development for a light cake, we won’t let it ferment.) and a quarter cup protein powder. I used MyProtein Butter Popcorn flavour https://www.myprotein.ie/sports-nutrition/impact-whey-protein/10530943.html here, as its buttery vanilla taste goes amazingly well with cake. But any of your favourite vanilla powder should be ok. Though I won’t give any guarantees for the flavour, as personally, I have not found any other protein powder yet, that I would really want in my cake.
The sugar content can be reduced by about ¼ cup, again due to the sweetness from the protein powder. It not only adds nutrition, but takes on several roles in improving the cake, which is why I keep adding it to many of my sweet baking recipes.
Shredded zucchini (courgette for those of you in Ireland) of course. I shredded it relatively coarse with my food processor, as I love the structure and green flecks it adds.
Usually for this recipe you’d leave all the moisture in, as the original from Sue Moran I used as blueprint (Which is amazing in its own right and can be found here) calculates with the liquid included. But since I’m adding sourdough discard, which has about ¼ cup water content, I squeeze out about as much from the shredded zucchini and leave the rest in.
A mix of baking powder and soda gives more rise. Poppy seeds add crunch and flavour that goes incredibly well with lemon.
For the fat source I used coconut oil instead of vegetable, as it’s healthier and adds a nice back note of coconut without being overpowering.
Not to forget the lemon. We are making Lemon Poppy Sourdough Zucchini Bread with Protein after all. The zest of a whole lemon goes into the batter, plus 3 tbsp juice. Then we use more juice to mix with icing sugar later for the glaze.
Adding thyme is optional but gives a lovely background flavour. Don’t worry, this will not taste savoury. It just adds this little “je ne sais quoi” to the cake.
The candied lemons on top are also optional but highly recommended. They are not just pretty, but also add a delicious sweet and zingy lemon hit when you bite into them. They are also incredibly easy to make. You just cook some lemon slices in a mix of sugar, lemon juice and water for 15min while you are making the batter and are sure to impress anyone who gets to eat one of these lovely little cakes.
You can make the Candied Lemon slices either before mixing the batter or while your cake is in the oven. I would do it before, to give them some time to dry later. Simply slice the lemons thinly, take out the pips if you find any. Bring water, sugar and lemon juice to a boil in a large saucepan and spread the lemon slices into the liquid, letting them simmer for about 15 minutes. Turn them gently once or twice. When done, spread them out on a try lines with baking parchment, to let them dry a bit. They will remain sticky. You can store any leftovers in an airtight container in the fridge for up to 2 weeks.
As most sponge cake recipes, this is pretty easy, but relies on you properly whisking sugar, butter and eggs (and in this case also the protein powder), to achieve the spongy texture.
I find this easiest in a blender. In this case my Nutribullet, which I bought initially to make smoothies, but am using so much for all kinds of recipes these days, that it has very much earned back the 100€ I invested and constantly lives on my counter.
The Zucchini can be shredded on a hand grater or on the grating attachment of a food processor. Squeeze out only about ¼ cup of liquid over a sieve with a measuring cup underneath, to keep enough in it for the batter.
From here it’s adding the wet to the dry ingredients, folding them in, but not too much. Just so all the flour is incorporated, as we don’t want to develop the gluten, to keep your Lemon Poppy Sourdough Zucchini Bread light and fluffy.
You can either make one large bread with this, which will need to bake for about 60-65 minutes or, as I did, these super cute mini loafs, which need to bake 25-28 minutes.
Let them cool before adding the glaze and candied lemon (if using), so the glaze can firm up.
For the lemon glaze, add the lemon juice very slowly, starting with 1 tbsp for 1 cup of icing sugar, mixing it in completely, before adding more. It will look too dry first, but the sugar will melt into it, trust me. Only add more juice if it’s too thick to spread after all juice is incorporated.
This bread keeps for about 3-4 days covered, but the icing will melt a bit.
So if you want to make this for guests ahead of time, I would add the lemon glaze about 1h before serving for the prettiest white cover. Maybe garnish with a bit of thyme if you used it, for more contrast.
The bread (or mini loafs) freezes well and comes back to life amazingly with just a few minutes in the air fryer or oven, if you like a crisp crust as I do. The icing does not freeze too well, but if you don’t mind the looks, it works, as it seeps into the cake and adds even more flavour, giving you a quick and nutritious Lemon Poppy Sourdough Zucchini Bread with Protein whenever a craving strikes.
Looking for more recipes with Protein? Click here.
How about Sourdough Chocolate Banana bread with Protein? Or maybe you are more of a Banoffee Pie lover, but would prefer one with lower calories and protein?
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?
If you enjoyed this recipe, please share. It helps me a lot. 🙂
Lemon Poppy Sourdough Zucchini Bread with Protein
- 2 large eggs
- ½ cup coconut oil melted and cooled
- Zest of 1 lemon
- 3 tbsp lemon juice
- ¼ cup protein powder I used MyProtein Buttered Popcorn, but vanilla is good too
- ¾ sugar I used golden caster sugar here, but white is just fine
- 1 tsp baking powder
- ½ tsp baking soda
- 1/2 tsp kosher salt
- 1 cup plain flour
- ½ cup fine whole wheat flour
- 2 cups shredded zucchini
- 3 tbsp poppy seeds
- 1 tbsp finely chopped thyme leaves
- 1 cup icing sugar
- 1.5 tbsp lemon juice
- Candied lemon slices:
- 3 lemons. 2 sliced thinly 1 juiced
- 1 cup granulated sugar
- 1 cup water
- Candied Lemon Slices:
- Slice 2 lemons thinly, removing any seeds.
- In a large saucepan, combine water, granulated sugar, and the juice of 1 lemon. Bring the mixture to a boil.
- Add the lemon slices to the boiling syrup and let them simmer for about 15 minutes, gently turning them once or twice.
- When the lemon slices are translucent and the syrup has thickened slightly, remove them from the syrup and place them on a tray lined with parchment paper to cool and dry. They will remain slightly sticky.
- You can store any leftover candied lemon slices in an airtight container in the fridge for up to 2 weeks.
- Batter Preparation:
- Preheat your oven to 350°F (175°C). Grease and flour a standard-sized loaf pan or prepare mini loaf pans.
- In a blender (such as a Nutribullet) or with a hand mixer, combine the eggs, coconut oil, lemon zest, lemon juice, protein powder, and sugar. Blend until well combined and smooth.
- In a separate mixing bowl, whisk together the baking powder, baking soda, kosher salt, plain flour, and whole wheat flour.
- Add the shredded zucchini to a sieve and place it over a measuring cup. Squeeze out approximately ¼ cup of excess liquid from the zucchini.
- Pour the wet mixture from the blender into the dry ingredients. Add the shredded zucchini, thyme (if using) and poppy seeds. Gently fold everything together until just combined. Be careful not to overmix; you want the batter to be just combined.
- Pour the batter into the prepared loaf pan(s).
- If using a standard-sized loaf pan, bake for about 60-65 minutes. If using mini loaf pans, bake for 25-28 minutes, or until a toothpick inserted into the centre comes out clean.
- Allow the bread to cool in the pan for about 10 minutes, then transfer it to a wire rack to cool completely.
- Lemon Glaze:
- In a small bowl, combine the icing sugar and lemon juice.
- Add the lemon juice very slowly, starting with 1 tbsp, and mix it in completely before adding more. Continue adding lemon juice until the glaze reaches your desired consistency. It will appear dry at first, but the sugar will gradually melt into it.
- Once the bread has cooled, drizzle the lemon glaze over the top.
- Decorate the bread with the candied lemon slices that you prepared earlier.
So if you want to make this for guests ahead of time, I would add the lemon glaze about 1h before serving for the prettiest white cover. Maybe garnish with a bit of thyme if you used it, for more contrast. The bread (or mini loafs) freezes well and comes back to life amazingly with just a few minutes in the air fryer or oven, if you like a crisp crust as I do. The icing does not freeze too well, but if you don’t mind the looks, it works, as it seeps into the cake and adds even more flavour, giving you a quick and nutritious Lemon Poppy Sourdough Zucchini Bread with Protein whenever a craving strikes. Calories: Approximately 280-320 calories
Fat: Approximately 12-15 grams
Protein: Approximately 4-6 grams
Carbohydrates: Approximately 40-45 grams
Sugar: Approximately 25-30 grams