Originally found this recipe on the official Castello Cheese website, and got around to making it just recently for a birthday celebration.
https://www.castellocheese.com/en-ca/recipes/mussels-with-blue-cheese-cream-sauce/
We got the mussels on a quick sale at the local grocer, had an use by date for the next day.

Mussels in Blue Cheese Sauce
Cleaned the mussels under cold running water, and tap tap to make sure they 're still alive and not gonna give us explosive Poopers
Print RecipeNotes
Clean the mussels under cold running wateR. And tap tap on each one to make sure they 're still alive & not gonna give you explosive Poopers.