Preheat the oven to 350 degrees F (175 degrees C). Line a cupcake pan with 12 paper liners.

Beat sugar and butter together in a bowl using an electric mixer until light and fluffy. Beat in egg and vanilla extract. Mix in baking powder, baking soda, and salt. Alternate adding flour and milk, stirring until just combined. Fill prepared pan with batter.

Bake in the preheated oven until lightly browned on top, about 18 minutes. Cool in the pan for 10 minutes, then remove to wire racks to cool completely.