3 rhubarb and berry coffee cake Recipes

yellow cake mix, divided, brown sugar, cold butter or 2 tbsp margarine, chopped walnuts, eggs, sour cream, chopped fresh rhubarb, sliced fresh strawberries, cream cheese frosting (optional)

yellow cake mix (regular size), divided, brown sugar, butter, chopped walnuts, sour cream, eggs, king arthur unbleached all-purpose flour, chopped fresh or frozen rhubarb, sliced fresh strawberries, cream cheese frosting or vanilla ice cream, optional