This deceptively simple cake is unbelievable delicious. My personal variation on Bon Appetit's Best, what BA considers an essential recipe. Three changes worth noting:
A few substitutions to the original BA recipe make the cake denser.
I use three 6" pans instead of 9" pans, and we don't cut them into multiple layers (I'm not lazy, I just don't see the need for all that extra work)
The original recipe called for sour cream frosting. I'm ditching the tart, sour cream, and going with a more traditional chocolate.
3 ½ cups cake flour
½ cup corn starch
2 teaspoon baking powder
1½ teaspoon baking soda
1½ teaspoon kosher salt
1½ cups Kefir
2 teaspoon vanilla extract
2 cups sugar
1 ½ cup (3 sticks) unsalted butter, room temperature
½ cup (packed) light brown sugar
1 vanilla bean, split lengthwise
6 large egg yolks
3 large eggs
Arrange racks in upper and lower thirds of oven; preheat to 350°. Lightly butter three 6” cake pans with butter.
Combine flour, cornstarch, baking powder, baking soda, and salt in a large bowl. Combine Kefir and vanilla in a medium bowl.
Mix butter, sugar and brown sugar in another large bowl. Using an electric mixer, beat butter mixture until light and fluffy, 3–4 minutes. Scrape in seeds from vanilla bean. Add yolks and eggs, beating to blended, 5-6 minutes, occasionally scraping down sides and bottom of bowl. Mixture will be light and pale yellow
Reduce mixer speed to low, add dry ingredients in 2 additions, alternating dry ingredients with Kefir mixture.
Divide batter evenly among prepared pans. Smooth tops.
Bake cakes on top until cakes are light golden brown, the centers spring back when gently pressed, and a tester inserted into the centers comes out with a few moist crumbs attached, about 40 minutes.
Transfer cakes to wire racks; let cool. Invert cakes onto racks and let cool completely.
Using a long knife, remove top dome and any bumps from each cake to create a flat surface.
½ cup (1 stick) unsalted butter
8oz powdered sugar
6oz cocoa powder
6oz whipping cream
1 tablespoon vanilla extract
1 teaspoon salt
Beat butter and sugar until fluffy, 2-3 minutes
Alternate between adding cocoa powder and whipping cream, beat until fully incorporated, 2-3 minutes
Add vanilla and salt, beat until incorporated, 1-2 minutes
Place 1 cake layer on a cake stand.
Spoon ½ cup frosting over top; using an offset spatula or the back of a spoon, smooth frosting to edge of cake, creating an even layer. Place another cake layer on top. Repeat with frosting and remaining cake layer.
Spread remaining frosting over top and sides of cake.
Image: Sophisticated Gourmet