Preheat your oven to 350 degrees. Grease a 9-inch springform pan with coconut oil or butter and set aside.

In a bowl whisk together the gluten free flour, yellow cornmeal, baking powder, xanthan gum and salt.

In the bowl of your mixer beat together the granulated sugar and eggs. Add the milk, vanilla and melted coconut oil. Beat until combined.

Add the dry ingredients to the wet ingredients and beat just until they are combined.

Pour the cake batter into the greased 9-inch springform pan. Place the plum halves on top of the cake batter to cover the entire top.

Bake at 350 degrees for 45-50 minutes or until a toothpick in the middle of the cake comes out clean.

Let the cake cool for at least 10 minutes before releasing the outside of the pan.

Serve warm or cooled.