In a large pot, add the fresh mussels and enough water to cover the bottom, then cover and heat over medium-low for about 5-7 minutes. Watch for the shells to open; this indicates they are ready. Once opened, remove them from heat, let cool, and carefully separate the shells, placing the mussel meat back into the shell halves.

In a saucepan over medium heat, melt the unsalted butter until foamy. Add the finely minced garlic and sauté until fragrant and tender, about 1-2 minutes. Stir in breadcrumbs and sauté for another minute, then pour in ½ cup of fresh milk while stirring continuously until the mixture thickens, about 3-5 minutes. Finish with a pinch of salt.

Line a baking tray with parchment paper. Arrange the mussel shells with the meat inside on the tray, then spoon the creamy garlic-bechamel sauce over each mussel. Grate the quick-melt cheese over the top.

Preheat your oven to 355°F (180°C). Once ready, bake the stuffed mussels for 10-15 minutes until the cheese is melted, bubbly, and golden brown.