I make this quite frequently
1 can tuna (drained)
1/3 to 1/2 C chopped celery
1 to 2 tsp lemon juice (optional)
1/4 to 1/3 C Miracle Whip
Mix together.
Separate 4 hamburger buns and spread w/tuna mixture. Top with 1/2 slice Velveeta and sprinkle with garlic salt.
Spray cookie sheet w/Pam and Bake at 350 for 20 minutes. Makes 8 buns.