This plum cornmeal cake is a delicious pairing of stone fruit with a more savory base layer. But when baked, the two work so well together, creating a not-too-sweet combination that speaks to the flavors of the summer season!
Lightly brush butter inside an 8-inch round cake pan. Line the bottom with parchment and brush with butter. Lay pieces of sliced plum around the pan covering the bottom. Sprinkle with brown sugar and cinnamon. Set aside.
In a large bowl, combine the flour, cornmeal, sugar, and baking powder. Whisk to combine.
In a separate bowl, combine the melted butter, eggs, vanilla extract, and buttermilk. Whisk until smooth and add to the dry ingredients.
Whisk until just combined with a few dry streaks remaining and pour over the prepared plums. Smooth to an even layer and bake in preheated oven until a wooden skewer inserted in the middle comes out clean, 40-55 minutes.
Remove from oven and cool in pan for 15 minutes. Invert onto serving dish and discard parchment paper. This can be served warm or at room temperature.