- Rhubarb Filling:
- 4 cups chopped rhubarb
- 2 tablespoons lemon juice
- 1 cup white sugar
- 1/3 cup cornstarch
- 1 (20 ounce) can cherry pie filling
- Cake:
- 3 cups all-purpose flour
- 1 cup white sugar
- 1 teaspoon baking powder
- 1 teaspoon baking soda
- 1/2 teaspoon salt
- 1 cup cold butter, cubed
- 1 cup buttermilk
- 2 eggs, lightly beaten
- 1 teaspoon vanilla extract
- Topping:
- 1 1/2 cups white sugar
- 1 1/2 cups all-purpose flour
- 1/2 cup cold butter, cubed
- Combine rhubarb and lemon juice in a large saucepan over medium-low heat; cook, stirring often, for 5 minutes.
- Mix 1 cup sugar and cornstarch together in a bowl; stir into rhubarb mixture. Cook and stir until rhubarb mixture is thickened and bubbling, about 5 minutes. Stir in pie filling; remove from heat and cool filling, about 10 minutes.
- Preheat oven to 350 degrees F (175 degrees C). Grease a 9×13-inch baking dish.
- Combine 3 cups flour, 1 cup sugar, baking powder, baking soda, and salt in a large bowl; cut in 1 cup cubed butter until mixture resembles fine crumbs.
- Beat buttermilk, eggs, and vanilla extract together in a separate bowl; add to flour mixture and stir just until batter is moistened.
- Spread a little more than half of the batter into the prepared baking dish; top with cherry-rhubarb filling. Drop teaspoonfuls of remaining batter over filling.
- Combine 1 1/2 cup sugar and 1 1/2 cups flour in a bowl; cut in 1/2 cup cubed butter until mixture resembles coarse crumbs. Sprinkle mixture over batter.
- Bake in the preheated oven until a toothpick inserted in the center comes out clean, 40 to 45 minutes.