Pre-heat the oven to 350F
Crumple up 1-2 sheets of foil. Unravel it and lay it on a cookiesheet or baking pan. (You may need to use 2 trays, depending on how many mussels you have)
Gently squeeze each mussel against the shell over the sink or bowl to remove any excess water that ice may have left behind and place them on the foil.
Once all the water has been removed, pull each mussel out of the shell and place it back in its original place. This will make easier to eat once the cheese has been baked onto the mussels.
Spread approximately 1 heaping teaspoon of garlic cream cheese on each mussel, mainly focusing around the top and bottom part of the shell where there are large gaps. Place the mussel back on the foil. Adjust the mussels so they are sitting straight and are not tilted. We don't want any of that yummy cheese to slide off while it's baking.
Sprinkle some cheddar over each mussel
Put the tray of mussels in the oven on the middle rack and bake for 10-15 minutes
Once it has finished baking, set the oven to broil, and broil it for 4-6 minutes to brown the cheddar. Make sure you are watching it during this step so they don't burn!
Once the cheese starts to brown and bubble, it's done! Serve it right away while it's hot and cheesy!