Sift together flour, baking powder, soda and salt. Add nuts; mix well and set aside. Melt butter in saucepan and remove from heat. (if margarine is used, add 1 tablespoon hot water.) Add brown sugar and beat well. Let cool. Add egg and vanilla and blend. Add flour mixture, a small amount at a time, mixing well after each addition. Spread in greased8 x 20 cm pan. Sprinkle chocolate chips over top. Bake at 180ºC or 20-25 minutes. Do not overbake. Cool in pan and cut in squares. If doubling recipe, bake in 9 x 30 cm pan. Recipe By : Southern Sideboards by the Junior League of Jackson, MS