Makes two 9-inch round cakes
16 tablespoons (2 sticks) unsalted butter, at room temperature, plus more for greasing pans
1½ cups (7.2 ounces) all-purpose flour, plus more for dusting pans
1½ cups (6 ounces) cake flour
1 tablespoon baking powder
½ teaspoon salt
1¾ cups (12.15) granulated sugar
4 large eggs, room temperature
2 teaspoons vanilla extract
1¼ cups milk, at room temperature
1. Preheat the oven to 350˚ F. Line the bottoms of two 9-inch round cake pans with parchment paper. Butter and flour the edges of the pans, tapping out the excess; set aside. In a medium bowl, combine the all-purpose flour, cake flour, baking powder, and salt; whisk together to blend well and set aside.
2. In the bowl of an electric mixer, combine the butter and sugar. Beat on medium-high speed until light and fluffy, about 4 minutes, scraping down the bowl as needed. Mix in the eggs one at a time, beating well after each addition. Blend in the vanilla. With the mixer on low speed, add in the dry ingredients in three additions, alternating with the milk. Beat each addition just until incorporated.
3. Divide the batter between the prepared baking pans. Bake, rotating the pans halfway through baking, until the cakes are golden and a toothpick inserted in the center comes out clean, 30-35 minutes. Transfer the pans to a wire rack and let cool 20 minutes. Run a knife around the edge of the pans to help remove the cakes. Invert the cakes onto the rack and peel off the parchment. Let the cakes cool completely before frosting. Level the cakes if necessary.