Rinse fresh mussels under cold water to remove any grit. Use a brush to scrub their shells and pull off any beards.

In a large pot, add a cup of water, place a steaming rack inside, and bring to a boil. Add the mussels, cover, and steam for 5-7 minutes or until the shells open.

Discard any mussels that remain closed.

In a small saucepan, melt butter over medium heat. Add minced garlic and sauté for 1 minute until fragrant.

Sprinkle in breadcrumbs, mix, and toast slightly before adding milk gradually. Stir until thickened, about 4-5 minutes, and season with salt to taste.

Preheat the oven to 355°F (180°C). Line a baking tray with parchment paper.

Carefully remove mussels from their shells, reserving half the shells. Place cleaned mussels back in their shells and fill with the garlic-bechamel sauce.

Sprinkle quick-melt cheese over each mussel to ensure they are well-coated.

Place mussels on the baking tray and bake for 10-15 minutes until cheese is bubbly and slightly crisp.

Allow to cool briefly before serving warm as an appetizer.