Frozen Sour Cherry Sponge

Ingredients: 1 teaspoon baking powder,Frozen cherries,7 eggs, separated,7 tablespoons flour,1 cup sugar,3 tablespoons sunflower oil (or any oil without flavor),2 teaspoons vanilla extract,Vanilla sugar, to sprinkle
Instructions:

1. Preheat oven to 190 C (medium heat)
2. Put the baking sheet in tray
3. Beat the egg whites well, with a pinch of salt, until hard peaks are formed
4. Mix the egg yolks, sugar, oil, vanilla with electric mixer until creamy
5. Mix baking powder in yolks mixture
6. Put the yolks into egg whites and fold with a spatula with care not to flatten the composition
7. Add sifted flour and mix in the same way
8. Pour batter in pan and spread it evenly
9. Sprinkle a tablespoon of flour over cherries and stir
10. Put the cherries in the pan, evenly
11. Bake 25 minutes or until the sponge is cooked
12. Remove to a rack and sprinkle with vanilla sugar. Wait until is cooled (if you can)

Source