Plum Buckle

7 cups pitted and quartered plums

⅔ cup butter, softened

1 ½ cups white sugar

2 eggs

3 cups sifted all-purpose flour

1 tablespoon baking powder

½ teaspoon salt

2 cups milk

2 teaspoons vanilla extract

1 cup white sugar

½ cup butter, softened

¼ cup all-purpose flour

1 teaspoon cinnamon

Preheat oven to 350 degrees F (175 degrees C). Grease a 9x13-inch baking dish.

Place the plums into the bottom of the prepared baking dish. In a large bowl, mash together 2/3 cup butter with 1 1/2 cup of white sugar until the mixture is smooth and creamy. Beat in eggs, one at a time. Stir in 3 cups of flour, the baking powder, and salt. Mix in the milk and vanilla extract to make a smooth batter. Pour the batter over the plums. Mix 1 cup of sugar, 1/2 cup of butter, 1/4 cup of flour, and cinnamon together in a bowl to make a crumbly topping; spread over the batter.

Bake in the preheated oven until a toothpick inserted in the center of the cake comes out clean, 45 to 50 minutes.