Sour Cherry Crumb Cakes

From Martha Stewart

Frozen dark sweet cherries may be substituted for fresh sour cherries. Let frozen cherries thaw before using.

Makes 16 squares

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
    1/4 teaspoon salt
    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 - 1lbfresh sour cherries, pitted, or frozen dark sweet cherries

Method
Preheat oven to 350°F. Butter a 9-inch square baking dish, and dust with flour, tapping out excess.
   
Make the topping: Stir together butter, flour, sugars, salt, and cinnamon.
   
Make the cakes: Whisk together flour, baking powder, and salt in a bowl. With a mixer, cream butter and granulated sugar in another bowl until pale and fluffy. Beat in eggs and vanilla. Working in alternating batches, add flour mixture and buttermilk, beginning and ending with flour mixture. Beat until just combined. Pour into prepared dish, and smooth with an offset spatula. Dot top with cherries, and sprinkle with crumb topping.
   
Bake until golden and a tester inserted into center comes out clean, about 1 hour. Let cool before cutting.