Merks Coffee Cake (Gma Klenk's famous recipe??)

Why I Love This Recipe
I'm not sure but I think this is the coffee cake that always disappears so fast at Christmas - it's that good!
Ingredients You'll Need
1/2 cup shortening
1/2 cup sugar
1 tsp vanilla
3 eggs
2 cups flour
1 tsp baking powder
1 tsp baking soda
1/2 pint sour cream
Filling and Topping:
6 T margarine
1 cup brown sugar
2 tsp cinnamon
1 cup chopped nuts (pecans or walnuts)
Directions
Cream together the shortening, sugar, and vanilla; add the eggs one at a time, beating well. Mix together the dry ingredients: flour, baking powder, and baking soda. Add the dry ingredients to the creamed mixture, alternating with the addition of the sour cream. Beat well between each addition.
Mix the ingredients together for the filling/topping. Beat well until creamy; add the nuts.
Place 1/2 of the batter in a 10-in greased and floured tube or bundt pan. Sprinkle lightly with about 1/2 of the filling/topping mixture. Add the rest of the batter then more filling/topping mixture until gone.
Bake at 350° for 50 minutes. Once cooled, invert onto a plate/platter.