Sour Cherry Crumb Cakes

Name: Sour Cherry Crumb Cakes
Ingredients: FOR THE TOPPING; 2 ounces (4 tablespoons) unsalted butter, melted, plus more for dish; 3/4 cup all-purpose flour, plus more for dish; 1/4 cup granulated sugar; 1/4 cup packed light-brown sugar; 1/4 teaspoon salt; 1/4 teaspoon ground cinnamon; FOR THE CAKES; 1 1/2 cups all-purpose flour; 1 teaspoon baking powder; 4 ounces (1 stick) unsalted butter, softened; 3/4 cup granulated sugar; 2 large eggs; 1 teaspoon pure vanilla extract; 1/4 cup buttermilk; 2 1/2 cups (1 pound) fresh sour cherries, pitted, or frozen dark sweet cherries