Serves 6 to 8
Preheat oven to 350 degrees.
In the bowl of an electric mixer fitted with the paddle attachment, cream 1/2 pound butter and sugar on medium speed until light and fluffy. While machine is running, add eggs and vanilla and mix until incorporated.
Sift together 3 cups flour and baking powder. Slowly add flour mixture to batter and mix on low speed just until a dough is formed. Very gently, by turning the mixer on and then off, fold chips and nuts into dough.
Once dough is blended, grease a 9-by-9-inch baking pan with remaining butter and dust with 1 tablespoon flour. Pour batter into pan and place in preheated oven. Bake for 25 to 30 minutes, or until set yet still moist.