Prep the mussels: Clean the mussels under running water. Discard any that are cracked or stay open when tapped.
Open them: Steam mussels with a splash of water until they open. Remove from heat.
Half-shell them: Remove the top shell. Place each mussel on its half shell on a baking tray.
Make the sauce: In a frying pan over medium-high heat, warm olive oil. Add garlic and cook briefly until fragrant (do not burn it). Add mussels, white wine, salt, pepper, parsley, and tomato sauce. Simmer 5 minutes. Remove from heat.
Top and broil: Spoon a little of the mixture over each mussel. Sprinkle with panko and Parmesan.
Broil: Place under the broiler until golden brown and crisp. Watch closely, this goes fast.
Serve immediately.