Name: White Vanilla Bean Cake with Balsamic Strawberry and Mascarpone Filling
Cook time: P0Y0M0DT1H20M0.000S
Total time: P0Y0M0DT2H20M0.000S
Yield: One 8-inch, 3-layer cake
Ingredients: Nonstick spray; 5 cups all-purpose flour; 4 cups cake flour; 4 teaspoons baking powder; 2 teaspoons baking soda; 2 teaspoons fine salt; 16 large egg whites, lightly beaten; 4 cups sour cream; 2 cups milk; 6 tablespoons clear vanilla extract; Seeds from 2 vanilla beans; 1 pound unsalted butter, softened; 5 1/3 cups granulated sugar; 1 pound fresh strawberries; 1/2 cup granulated sugar; 1/3 cup balsamic vinegar; 2 tablespoons freshly-squeezed lemon juice; 1 cup mascarpone cheese, room temperature; 2 cups heavy cream; 1/2 cup confectioners' sugar; 1 tablespoon clear vanilla extract; 1 pound unsalted butter, softened; 2 cups shortening; 2 pounds confectioners' sugar, sifted; 4 teaspoons clear vanilla extract

Directions

Special equipment:

parchment paper; three 8-inch round cake pans

Preheat the oven to 325 degrees F. Spray three 8-inch round pans with nonstick spray and line them with parchment paper. Spray the paper.
Sift together the all-purpose flour, cake flour, baking powder, baking soda and salt in a large bowl. Whisk together the egg whites, sour cream, milk, vanilla and vanilla bean seeds in another large bowl.
Beat the butter and sugar with a paddle attachment until light and fluffy. Alternate beating in the flour mixture and the egg mixture, adding the flour mixture in 3 additions and the egg mixture in 2, starting and ending with the flour.
Fill each cake pan with 2 1/2 cups of batter and bake until a toothpick inserted in the center comes out clean, about 40 minutes. Cool the cakes in the pans for 15 minutes, then flip them onto a cooling rack to cool completely.
For the filling: Put the strawberries, granulated sugar, balsamic vinegar and lemon juice in a medium saucepan over medium heat, bring the mixture to a simmer, and cook until it gets to a syrupy reduction, about 30 minutes.
Cool completely.
Beat the mascarpone in a medium bowl until smooth. Whip the heavy cream until light and fluffy in another bowl; just before it is finished, whip in the confectioners¿ sugar and vanillia extract. Fold in the strawberry mixture.
For the frosting: Cream the butter and shortening until light and fluffy, then beat in the confectioners' sugar and vanilla extract.
To assemble the cake: Put 1 cake layer on a cake board or platter. Spread half of the filling mixture on top. Repeat with another cake layer. Frost the cake with the buttercream frosting and serve.