1/4 lb. butter
1 tbsp. grated onion
1 tbsp. poppy seeds
1 tbsp. prepared mustard
12 slices Canadian bacon
12 slices cheese
12 buns

Mix first four ingredients and spread on buns. Top with bacon slices and cheese. Wrap in foil and bake at 300 for 20-30 minutes or until heated through and cheese melts.