Preheat the oven to 350°F (175°C) and line two 12-cup muffin tins with cupcake liners. Make sure the oven is fully heated for even baking.

In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.

In a smaller bowl, whisk the sour cream and milk until smooth and well combined.

Beat the butter on high speed for 4–5 minutes until pale and fluffy. This step helps create a light texture.

Add the sugar and continue beating for about 2 minutes until the mixture looks airy.

Mix in the eggs one at a time, then stir in the vanilla extract. If the mixture looks slightly curdled, keep mixing until smooth.

Gently fold in the dry ingredients in three additions, alternating with the sour cream mixture. Begin and end with the dry ingredients, mixing just until combined.

Fill each cupcake liner about ⅔ full using a scoop for even portions.

Bake for 12–14 minutes, until the tops are lightly golden and spring back when touched. A toothpick inserted in the center should come out clean.

Let the cupcakes cool completely on a wire rack before frosting so the topping holds its shape.