Mom's Shoofly Coffee Cake

3/4 c. soft butter
1 c. sugar
3 eggs
1 1/2 t. vanilla
1/2 c. light molasses
1 1/2 t. baking powder
2 t. soda
1/4 t. salt
3 c. flour
1 1/2 c. sour cream
Filling:
1/2 c. brown sugar, packed
1/2 c. chopped walnuts or pecans
1 1/2 t. cinnamon

Heat oven to 350. Grease a tube pan or 2 loaf pans. Combine butter, sugar, eggs, vanilla and molasses in large mixing bowl. Beat on medium speed 2 minutes (or 300 vigorous hand strokes). Stir together baking powder, soda, salt, and flour). Add to cream mixture, alternating with sour cream. For a tube pan, pour 1/3 batter into pan, sprinkle with 1/3 filling (6 T). Repeat. For loaf pans: pour 1/4 batter in and sprinkle with 1/3 filling. Repeat. Sprinkle each with filling. Bake 55-60 minutes. Cool 10 minutes before removing from pan.