Perfect Vanilla Cupcakes

Preheat oven to 350° and line two muffin tins with liners. In a large bowl using hand mixer (or in the bowl of a stand mixer), beat together butter and sugar until light and fluffy. Add eggs, one at a time, beating well after each addition. Add vanilla and mix until combined. In another large bowl whisk together flour, cornstarch, baking powder, and salt. Add half of the dry ingredients to the wet ingredients, beating until just combined. Pour in the milk and mix until fully incorporated. Add remaining dry ingredients and stir until just combined. Fill cupcake liners 3/4 full with batter. Bake until slightly golden on top and a toothpick inserted into the middle comes out clean, about 25 minutes. Remove from pan and let cool completely before frosting.