1. Prepare, then bake gingerbread mix as package label directs, using 9-by-9-by-2-inch pan. Cool; split horizontally, but do not separate layers; cut into 9 squares.
2. Whip cream with mace. On bottom layer of each square heap a tablespoonful of whipped cream; top with peach slices. Cover with top squares; then top with rest of cream and a few peach slices. Refrigerate until serving time.