1/2 c. grated Swiss cheese
1/2 c. sliced mushrooms
1 tbsp. chopped onions
1/2 c. cooked tuna
1/4 c. mayonnaise
2 English muffins, split

Combine all ingredients in a bowl. Stir until blended. Spread over muffins. Bake at 400 degrees for 10 minutes.

Any cooked seafood may be substituted for the tuna.