Yellow Cupcakes

Arrange racks in lower and upper thirds of oven; preheat to 400°. Line two standard 12-cup muffin tins with cupcake liners.

Whisk flour, sugar, baking powder, salt, and baking soda in the bowl of a stand mixer fitted with the whisk attachment. Add butter, buttermilk, and oil and beat on medium speed, scraping down sides of bowl, until smooth.

Whisk egg yolks, egg, and vanilla in a medium bowl until smooth. Add egg mixture to flour mixture in 2 additions, beating well between additions. Continue to beat on medium speed until mixture is homogenous and very thick, about 2 minutes.

Divide batter evenly among muffin cups, filling two-thirds full (a level ⅓ cup batter per cupcake). Bake 5 minutes, then reduce oven temperature to 350°. Continue baking, rotating pans halfway through, until cupcakes have domed and spring back when touched in the center, 20–25 minutes. Transfer to a wire rack and let cool.

Do Ahead: Cupcakes can be made 1 day ahead. Store airtight at room temperature.