This is a classic Russian sponge cake. It has been made in Russia for centuries. Its beauty is in its rustic simplicity. In Russia, baking powder was not used as they did not have it, but we do, so the addition of baking powder only enhances the finished product.
6 large eggs, at room temperature
1 cup granulated white sugar
1 1/3 cups all-purpose flour
1/2 teaspoon baking powder
1 teaspoon vanilla extract
1 1/2 pounds (4 medium) Granny Smith or Bramley apples, divided use
Confectioners' sugar or cinnamon-sugar (optional)
Heat oven to 350 degrees F. Line bottom of an ungreased 9-inch round
springform pan with a circle of parchment paper. Butter the parchment paper and
the sides of the pan.
Add 6 eggs to the bowl of a stand mixer fitted with
whisk attachment, and beat on high speed for 1 minute until foamy. With the
mixer on, gradually add the granulated white sugar while beating at high s[eed
for 8 to 10 minutes or until s thick and fluffy ribbon forms. When you pull up
on the whisk, the ribbon of batter should sit for a few seconds on the surface
before incorporating back into the batter. If you are using an electric hand
mixer, beat for 10 to 12 minutes or until a thick and fluffy ribbon forms.
Meanwhile, peel and core the apples, chop into quarters, then slice into
1/4-inch bite-size pieces.
In a medium bowl, whisk together flour with
baking powder. Sift flour mixture into the beaten egg batter in 3 increments,
folding with a spatula between each addition, scraping from the bottom of bowl.
Stop mixing when you no longer see streaks of flour (don't over-mix). Fold in vanilla extract just until incorporated.
Fold in sliced apples,
reserving 1 cup for the top. Fold just until combined into batter then pour
batter into prepared springform pan. Spread batter evenly with a spatula (do not
tap the pan) and scatter remaining apple evenly over the top.
Bake for 50-55 minutes. Top will be golden brown.
Remove from oven and let rest in pan for 15 minutes.
Slide a thin spatula or knife around edges of pan to
loosen and transfer cake to a cake platter to cool.
When cake is at room
temperature, sift confectioners' sugar over the top or sprinkle a cinnamon-sugar
mixture over the top, whichever you prefer.