Rhubarb Strawberry Filling Directions:

In a medium saucepan combine; rhubarb, strawberries, water, lemon juice and lemon zest.

In a small bowl combine, sugar and cornstarch; add to the rhubarb mixture. Cook and stir 4 to 5 minutes or until thickened and bubbly, stirring constantly. Use an immersion blender to blend together. Set aside to cool.

Coffee Cake and Topping Directions:

In a large bowl, stir together: flour, sugar, baking soda, baking powder and salt. Cut in butter until mixture resembles fine crumbs. In a small bowl combine the eggs, buttermilk or sour milk and vanilla. Add to flour mixture, stir to moisten. Spread half the batter in a greased 13 x 9 baking dish. Spread cooled rhubarb-strawberry filling over batter in pan. Spoon remaining batter in small mounds over filling.

In a small bowl combine, 1/2 cup sugar and 1/2 cup flour. Cut in 1/4 cup cold butter, until mixture resembles fine crumbs. Stir in chopped walnuts. Sprinkle crumb mixture over batter in pan.

Bake at 350º oven for 40 to 45 minutes or until golden brown.