5 tbsp. butter
1 c. dark brown sugar
3/4 c. flour
1 egg
1 tsp. baking powder
1/4 tsp. salt
1/2 tsp. vanilla
1/2 c. chopped walnuts

Melt butter over low heat. In a bowl, stir butter and brown sugar until well combined. Stir in the egg. Beat in the flour, 1/4 c. at a time. Stir in the baking powder, salt, vanilla and walnuts, and mix well. Spread batter evenly in greased 8-inch square pan.

Bake at 325°F for 30 minutes, or until top is dry and tester comes out clean.