Step 1: Preheat the oven and prepare the pan

Preheat your oven to 350°F (175°C).

Grease an 8-inch springform pan, and line the bottom with parchment paper. Optionally line the sides for clean edges. Grease the paper as well.

Step 2: Beat eggs and sugar

In a large mixing bowl, combine 3 eggs and 1⅛ cups sugar.

Beat with an electric mixer until the mixture is pale, thick, and fluffy.

Step 3: Add dry ingredients and fat

In a separate bowl, sift together 2 cups all-purpose flour and 2½ tsp baking powder (or Pane Degli Angeli).

Gradually add the flour mixture to the egg mixture, alternating with ⅓ cup softened butter.

Mix until well incorporated, then stir in ⅓ cup Greek yogurt.

Step 4: Process the orange

Cut the entire orange (remove seeds but keep the peel) into chunks.

Place it in a food processor or blender and process until nearly pureed. The mixture should still have some texture but no large chunks.

Stir the processed orange into the batter.

If you’re using plain baking powder, add 1 tsp vanilla extract here.

Step 5: Pour and bake

Pour the batter into your prepared springform pan and level the top.

Bake for 50–60 minutes, or until a skewer inserted in the center comes out clean.

Remove from oven and let cool in the pan for about 15 minutes. Then release the springform and transfer the cake to a wire rack.