Preheat oven to 350 degrees Fahrenheit
In a medium-size mixing bowl, combine egg yolks, milk, vanilla, and cooled melted butter and stir.
Mix in cornmeal, flour, sugar, baking powder, and salt, stirring to incorporate - but do not over mix.
In a separate bowl, beat egg whites until stiff peaks form. Carefully fold them into the batter.
Pour into a greased 8x8 pan and bake for 40-45 minutes. Check with a toothpick to make sure it is cooked through.