Preheat oven to 375 degrees F. Grease a 9-inch cast iron skillet with butter or cooking spray.
In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.
In a large bowl, whisk together the melted butter and 3/4 cup of granulated sugar. Add the eggs one at a time, whisking until combined after each addition. Add the vanilla extract and milk and mix until combined.
Add the dry ingredients to the wet ingredients and mix until combined. Pour the batter into the greased skillet.
Arrange the sliced plums over the top of the batter. Sprinkle the remaining 2 tablespoons of granulated sugar over the top of the plums.
Bake in preheated oven for 45-50 minutes, or until a toothpick inserted into the center comes out clean. Allow to cool slightly before serving.
Plum Skillet Cake is an easy and delicious way to enjoy plums in a dessert.
Plums are an excellent source of vitamin C, potassium, and antioxidants.
The buttery topping gives the cake a crunchy texture that is irresistible.