Vanilla Chiffon Cake

Cooking spray
2-1/2 cups cake flour; more for the pans
1-1/2 cups granulated sugar
1-1/4 tsp. baking powder
1/4 tsp. baking soda
1 tsp. kosher salt
6 large egg yolks
4 oz. (1 stick) unsalted butter, melted and cooled slightly
2 Tbs. vegetable oil
2 tsp. pure vanilla extract
1 cup buttermilk
3 large egg whites
Position a rack in the center of the oven and heat the oven to 350°F. Spray two 8-inch round pans with cooking spray and flour them.

In a large bowl, combine the cake flour, sugar, baking powder, baking soda, and salt. Whisk to combine.

In a medium bowl, whisk together the egg yolks, melted butter, vegetable oil, and vanilla extract. Once combined, whisk in the buttermilk. (The buttermilk goes in last so that it doesn’t cause the melted butter to coagulate and create lumps.)

In the bowl of a stand mixer fitted with the whisk attachment (or in a large bowl using an electric hand mixer or a hand-held whisk), whisk the egg whites on medium-high speed until stiff peaks form, 5 to 7 minutes.

Pour the bowl of wet ingredients into the bowl of dry ingredients and fold them together with a rubber spatula until combined.

Using the spatula, gently fold the egg whites into the cake batter in three batches. Take care not to deflate the egg whites or overmix the batter.

Divide the batter evenly between the prepared pans. Bake until a toothpick inserted in the center of a cake comes out clean or with a few moist crumbs clinging to it, 25 to 30 minutes.

Transfer the cakes to a rack to cool in the pan for about 30 minutes. To invert, run a knife or thin metal spatula around the edge of one cake to help loosen it. Invert the cake onto a plate. Remove the cake pan. Place a cake plate on top of the cake, and invert it again so the cake plate is on the bottom. Repeat for the other cake. Let the cakes cool completely before filling, frosting, or storing.