Candied Blood Orange Slices:

1. Bring a pot of water to a boil and prepare a bowl of iced water.
2. Blanch the orange slices in boiling water for 2 minutes, then transfer them to the ice bath.
3. In a medium saucepan, combine sugar and water. Bring to a boil, swirling the pan occasionally until the sugar dissolves.
4. Once the syrup reaches 225°F/110°C, gently add the orange slices in layers.
5. Simmer until the syrup thickens and reaches about 230°F/115°C, ensuring the orange slices are evenly coated.
6. Using tongs or a fork, transfer the candied orange slices to a wire rack placed over a baking sheet. Allow them to cool for at least 1 hour.

Blood Orange and Pistachio Cake with Protein:

1. Preheat the oven to 375°F/190°C. Grease a springform and line the bottom with parchment paper.
2. In a large bowl, whisk together olive oil and brown sugar until mostly dissolved. Add eggs one at a time, mixing until light and foamy.
3. Stir in the blood orange zest, juice, and protein powder until smooth and foamy.
4. In a separate bowl, combine the flours, ground pistachios (reserving 1/4 cup for garnish), baking powder, baking soda, salt, and cinnamon.
5. Gradually fold the dry ingredients into the wet mixture until just combined. Be careful not to overmix.
6. Pour the batter into the prepared springform pan and bake for 30-45 minutes, or until a toothpick inserted into the centre comes out clean.
7. Allow the cake to cool in the pan for 10 minutes before transferring it to a wire rack to cool completely.

Blood Orange Icing:

1. In a bowl or small jug, combine the blood orange juice with icing sugar. Start with 2-3 tablespoons of juice and adjust to reach a thick but pourable consistency.
2. Drizzle the icing over the cooled cake, spreading it evenly with a spatula.
3. Allow the icing to set completely before decorating.

Decorate and Serve:

1. Arrange the candied blood orange slices on top of the cake and sprinkle with the reserved chopped pistachios.
2. Slice and serve the cake with a nice cup of tea or coffee.