Preheat the oven to 350°F, lining a 9-inch round cake pan with parchment paper and greasing the sides.

Combine cornmeal, flour, baking powder, and salt in a bowl. Whisk until evenly distributed.

Cream butter and sugar in a separate bowl until light and fluffy, about 3–4 minutes.

Add eggs one at a time, beating well after each addition. Stir in vanilla extract.

Alternate adding dry ingredients and milk, beginning and ending with the dry mix.

Pour the batter into the prepared pan, smoothing the top with a spatula.

Bake for 25–30 minutes until a toothpick inserted near the center comes out with just a few moist crumbs.

Cool the cake in the pan for 10 minutes, then transfer to a wire rack to cool completely.