Strawberry Rhubarb Coffee Cake

3 cups all-purpose flour
1 cup granulated sugar
1 teaspoon baking soda
1 teaspoon baking powder
1 teaspoon salt
1 cup butter or margarine
1 cup buttermilk
2 eggs, slightly beaten
1 teaspoon vanilla extract
1 recipe Rhubarb Filling
3/4 cup granulated sugar
1/2 cup flour
1/4 cup butter or margarine

In mixing bowl, stir together the 3 cups flour, 1 cup sugar, baking soda, baking powder and salt; cut in butter or margarine to fine crumbs. Beat together buttermilk, eggs and vanilla extract; add to dry ingredients. Stir to moisten. Spread half batter in greased 13 x 9 x 2-inch baking pan. Spoon remaining batter in small mounds atop filling.

Combine remaining sugar and flour; cut in 1/4 cup butter to fine crumbs. Sprinkle crumbs over batter in pan. Bake at 350 degrees F for 40 to 45 minutes. Makes 12 to 15 servings.

Rhubarb Filling
3 cups fresh or 13 ounces frozen unsweetened
    rhubarb, cut into 1-inch pieces
2 tablespoons lemon juice
1 cup granulated sugar
1 (16 ounce) package frozen sliced, sweetened
    strawberries, thawed
1/3 cup cornstarch

In saucepan, combine rhubarb and strawberries. Cook 5 minutes; add lemon juice. Combine sugar and cornstarch. Add to rhubarb mixture; cook and stir 4 to 5 minutes until thick. Cool.