Rhubarb Streusel Coffee Cake
2 cups flour
1 cup sugar
1 tablespoon baking powder
1 teaspoon baking soda
1/2 teaspoon salt
4 tablespoons butter
2 large eggs
1 cup buttermilk
2 teaspoons vanilla extract
1 1/4 pounds rhubarb
cut into 1-inch chunks to equal 4 cups

Streusel Topping
3/4 cup flour
1/2 cup packed brown sugar
6 tablespoons butter, slightly softened
1 teaspoon ground cinnamon

Preheat oven to 375°F. Grease and flour 9 x 13-inch metal baking pan. In medium bowl mix Streusel Topping; cover and refrigerate. In large bowl, combine flour, sugar, baking powder, baking soda, and salt. With pastry blender, cut in margarine or butter until mixture resembles large crumbs.

In small bowl, with fork or wire whisk, beat eggs with buttermilk and vanilla extract; stir into flour mixture just until flour is moistened. Spoon batter into baking pan. Place rhubarb chunks evenly over batter in baking pan. Break Streusel Topping into large chunks and scatter over rhubarb.

Bake coffee cake 45 minutes or until toothpick inserted in center comes out clean. Cool cake in pan on wire rack 15 minutes to serve warm. Or, cool to serve later.