Preheat oven to 350°F.
PROCESS mustard, margarine, onion, and poppy seeds until spreadable.
SLICE Millie Ray and Sons Yeast Rolls in half and flip top over.
ADD ham to bottom layer and top with cheese.
PLACE bottom layer onto large baking pan, then place on top layer.
COVER with aluminum foil and bake for 10-15 minutes.