Sponge cake with proteins for cake

Ingredients:

• 165 g soft butter
• 1.5 cups of sugar
• 2 cups premium flour
• 2 tsp baking powder
• 1/4 teaspoon salt
• 6 whites from large eggs
• 3/4 cup milk
• 2 tsp vanilla extract
• Special equipment: 2 round cake tins (23 cm in diameter and 5 cm deep) or 1 rectangular cake tin (23 cm x 33 cm x 5 cm), greased with butter. Line the bottom with parchment or waxed paper.

Preparation:

1. Place a rack on the middle shelf of the oven and preheat to 180°C.
   
   In a large bowl, beat the butter and sugar until light and fluffy. Mix the flour with the baking powder and salt. Combine the egg whites, milk, and vanilla extract. Fold 1/3 of the flour mixture into the creamed butter, then pour in half of the milk mixture. Continue adding the remaining ingredients, one at a time, beginning and ending with the flour mixture.
2. Pour the batter into the prepared pans and smooth the surface with a spatula. Bake for about 25-30 minutes, or until a toothpick inserted into the center comes out clean. Cool in the pans on a wire rack for 5 minutes, then invert, remove the parchment paper, and cool completely.
   
   
   Note
   
   To make a classic golden sponge cake, replace the egg whites with 3 large eggs and 1 yolk.