Clean crabs by removing gills and cutting off the eyes and mouth.
Place crabs on pan or aluminum foil. Place on grill over a low fire. Baste the crabs with the Lemon Butter Sauce. Cook for 5 to 6 minutes on each side. Continue to baste during cooking. Before serving, top each crab with a slice of tomato and a small amount of mozzarella cheese. Allow cheese to melt. Remove from grill. Serve immediately.
Lemon Butter Sauce:
Add lemon juice and other seasonings. Seasonings may be adjusted for personal taste. Allow to simmer for about 20 minutes.