Prep the pan: Heat oven to 350°F (175°C). Line a 12-cup muffin pan with paper liners. For best rise, use sturdy liners and avoid over-greasing.

Measure accurately: Lightly spoon flour into a measuring cup and level it off. This prevents packing the flour, which leads to dense cupcakes.

Cream the butter and sugar: In a large bowl, beat 1/2 cup softened unsalted butter with 1 cup granulated sugar on medium-high until pale and fluffy, about 2–3 minutes. Scrape the bowl halfway through.

Add oil and eggs: Beat in 1/4 cup neutral oil until glossy. Add 2 large eggs plus 2 large egg yolks, one at a time, mixing well and scraping the bowl after each. Stir in 2 teaspoons pure vanilla extract.

Mix dry ingredients: In a separate bowl, whisk 1 1/2 cups cake flour (or 1 1/3 cups all-purpose flour), 2 teaspoons baking powder, 1/4 teaspoon baking soda, and 1/2 teaspoon kosher salt.

Mix wet ingredients: In a measuring cup, whisk 1/2 cup whole milk with 1/4 cup plain yogurt or sour cream until smooth.

Combine in thirds: Add the dry ingredients to the butter mixture in three additions, alternating with the milk mixture (dry, wet, dry, wet, dry). Mix on low just until combined after each addition. Do not overmix.

Portion the batter: Divide batter evenly among liners, filling each about 2/3 full. Use a scoop for consistency.

Bake: Bake 16–20 minutes, until the tops are set, lightly golden, and a toothpick comes out with a few moist crumbs. Rotate the pan once if your oven has hot spots.

Cool: Let cupcakes cool in the pan 5 minutes, then transfer to a rack to cool completely before frosting.

Optional frosting: For an easy chocolate buttercream, beat 1/2 cup softened butter until creamy. Add 1 3/4 cups powdered sugar, 1/4 cup unsweetened cocoa, a pinch of salt, 1 teaspoon vanilla, and 2–3 tablespoons milk or cream. Beat until fluffy and spreadable.