1 pkg. yellow cake
1/2 c. light brown sugar
1/2 c. coarsely chopped pecans or walnuts
10-15 marshmallows, cut in half

Mix cake according to package. Spread the batter in well greased 9 x 13 inch pan. Arrange marshmallows (rounded side up) on top of batter. Mix brown sugar and nuts; put over top. Bake at 350 degrees for 35 minutes.