It might not beat pepperoni and mushroom, but give it a shot.
15 oz. can tomato sauce
Thyme, to taste
Oregano, to taste
1/2 lb. firm fish fillets (snapper, shark, lg. mouth bass, etc.)
1/2 lb. mozzarella cheese, sliced
1/2 c. black olives, diced
Heat tomato sauce in skillet with spices. Add fish fillets. Cover and poach for 10 minutes for each inch of thickness. If fillets are thick, you may need to turn them carefully. When done, lay cheese slices on top of each fillet and sprinkle with olives. Serve with spatula onto plate when cheese begins to melt. Variation: Use your favorite spaghetti sauce instead of the tomato sauce.