Gather all ingredients. Preheat the oven to 350 degrees F (175 degrees C). Grease and flour a 9-inch square cake pan.

Ingredients to make simple white cake.

Cream sugar and butter together in a mixing bowl. Add eggs, one at a time, beating briefly after each addition. Mix in vanilla.

Combine flour and baking powder in a separate bowl. Add to the wet ingredients and mix well. Add milk and stir until smooth.

Pour batter into the prepared cake pan.

Bake in the preheated oven until the top springs back when lightly touched, 30 to 40 minutes.