Turn tahong or mussels into an elegant appetizer with a cheesy baked topping, brightened by crunchy, lemony breadcrumbs.
A three-cheese mixture—cheddar, cream cheese, and grated Parm—crowns these mussels, forming a rich, melty topping balanced out by lemony breadcrumbs. Don’t let the ingredients list intimidate you; each step comes together quickly, and you can prepare the topping components in advance. Fast and fancy!
Prepare for baking: Preheat broiler to 400°F or 200°C. Line baking sheet with aluminum foil.
Blanch mussels: Add ½ cup water to a large pot over medium-high heat. Once boiling and steam emerges, reduce heat to medium. Add mussels and cover pot with a lid. Steam until mussels open slightly, 1 minute. Drain and set aside until cool to the touch.
Cook onions and garlic: Add reserved 2 tbsp butter to a pan over medium-low heat. Once melted, add onions and garlic to the pan and cook until soft and onions are translucent. Do not brown! Remove aromatics from heat and set aside to cool completely.
Prepare crumb topping: In a separate pan, heat extra virgin olive oil over medium heat. Add panko breadcrumbs and toast until lightly golden. Season with salt and remove from heat. Add lemon zest (save the lemon juice for finishing later) and stir until thoroughly combined. Set aside.
Prepare cheese mixture: Add rest of the softened butter in a mixing bowl. Add onion and garlic mixture, cheddar, Parmigiano Reggiano, cream cheese, and herbs. Season with salt. Stir to combine with a rubber spatula. Taste and adjust seasoning.
Prepare tahong: Remove and discard half of the shell from the mussels, keeping the side with meat attached. Transfer shells with meat to the foil-lined baking sheet. Working one piece at a time, spoon about 1 tsp of the cheese mixture and spread to cover thoroughly. Top with breadcrumbs. Repeat with remaining mussels, cheese, and breadcrumb mixture.
Bake: Bake mussels until thoroughly warmed, 4–6 minutes. Finish with lemon juice. Serve immediately.
