Ingredients :
1-1/2 cup sour cream
1 tablespoon vanilla bean paste
1 tablespoon of vanilla extract
4 cups cake flour
2-1/2 cups sugar
4-1/2 teaspoons baking powder
2 teaspoons of salt
1 cup unsalted butter, softened
1/4 cup canola oil
6 large egg whites, room temperature
2 large eggs, room temperature

instructions :
Preheat oven to 350°. In a small bowl, mix sour cream, vanilla paste, and vanilla extract until well blended. Leave to rest for 10 minutes. Line the bottoms with 3 greased 9-in. round baking molds with parchment; greasy paper.
Sift cake flour, sugar, baking powder and salt twice into a large bowl. Add butter and canola oil; beat until mixture is crumbly. Add the egg whites, one at a time, beating well after each addition. Add the eggs, one at a time, beating well after each addition. Stir in sour cream mixture until combined.
Transfer the batter to the prepared pans. Bake until a toothpick inserted in the center comes out clean, 30 to 35 minutes. Let cool in the pans 10 minutes before placing on wire racks; remove the paper. Cool completely. Frost the cake as desired.