Cream together brown sugar and shortening. Add egg and
flour, baking soda and salt together. Add flour mixture
to creamed mixture, alternately with buttermilk, beating
after each addition. Stir in rhubarb and chocolate chips.
into a greased 9 x 13 inch baking dish.
Combine topping ingredients.
over the cake batter. Bake at 350 degrees F. for 45