Preheat oven to 350º.
Grease tube pan, 10 x 4 inches or 2 loaf pans, 9 x 5 x 3 inches.
Combine butter, sugar, eggs and vanilla in large mixer bowl.
Beat on medium speed 2 minutes or 300 vigorous strokes by hand.
Mix in flour, baking powder, soda and salt alternately with sour cream
For tube pan, spread ⅓ of batter (about 2 cups) in pan and sprinkle with ⅓ of filling (about 6 T.); repeat 2 times. For loaf pans, spread ¼ of the batter in each pan and sprinkle each with ¼ of the filling; repeat.
Bake about 60 minutes or until wooden pick inserted in center comes out clean.
Cool slightly in pan(s) before removing.