Frosted Scotch Drops

1/2 c butter
1 1/2 c packed brown sugar
2 eggs
1 tsp vanilla
2 1/2 c flour
1 tsp baking soda
1/2 tsp baking powder
1/2 tsp salt
1 c sour cream
1/2 c chopped walnuts

Preheat oven to 375.

Cream butter and sugar. Add eggs and vanilla. Add dry ingredients alternately with sour cream. Chill for at least 2 hours. Drop by teaspoonfuls onto baking sheet. Bake at 375 for 10 minutes.

Frosting:
1/4 c butter
2 c powdered sugar
2 to 3 Tbsp sour cream

Mix together butter and sugar. Add sour cream 1 Tbsp at a time, until frosting consistency.