Cream Margarine, sugar and eggs.
Fold in Sour Cream and Vanilla.
Add Flour, baking powder and Salt.
Generously Grease bundt pan.
Add half batter to bundt pan and sprinkle with cinnamon and Brown sugar mixture.
Add rest of batter over mixture.
Bake at 350 degrees for 50 to 60 minutes.
Cool 2-3 hours in pan.
Remove from pan and sift powdered sugar on top.
Serve alone or with berries and whipped cream.