Toss all the ingredients together (except the mussels) and place a couple of spoons of the mixture on top of the mussel.
Place on a ready grill until the cheese is melted--remember that blue cheese really doesn't melt that much, but you want to make sure the mussel meat is warm through (10 plus minutes).
Notes
Serving Suggestions: Other Combination you can try on the Mussels on the Half Shell:
Blue cheese, Bacon and Sauteed Onion
Bacon, Sauteed Onion, Barbeque sauce and Cheddar Cheese
Bacon, Sauteed Onion, Jalapeno, Cheddar Cheese
Sauteed Onions, Bourbon, Bacon, Black Pepper and Cheddar Cheese
Salted Butter, Toasted Almonds, Lemon and Chopped Parsley
Bacon, Sauteed Onion, Smoked Gouda and Diced tomato