1 (7 oz.) can tuna
3/4 c. chopped celery
1/2 c. Velveeta
1 sm. onion, chopped
1/4 c. mayonnaise
Salt and pepper to taste
6 hamburger buns

Preheat oven to 350 degrees. Butter hamburger buns. Fill with tuna mixture. Wrap in aluminum foil and bake 15 minutes (until cheese melts).