2 cups all-purpose flour
1 cup sugar
1 tablespoon baking powder
1 teaspoon baking soda
1/2 teaspoon salt 4 tablespoons margarine or butter (1/2 stick)
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 (Below)
Preheat oven to 375 degrees F. Grease and flour 13- by 9-inch metal baking pan. Prepare Streusel Topping; cover and refrigerate. In large bowl, combine flour, sugar, baking powder, baking soda, and salt. With pastry blender or two knives used scissor-fashion, 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.
STREUSEL TOPPING:
In medium bowl, with hand, mix 3/4 cup all-purpose flour, 1/2 cup packed light brown sugar, 6 tablespoons margarine or butter (3/4 stick), slightly softened, and 1 teaspoon ground cinnamon until mixture comes together.
