Heat a deep skillet or a pot with 3 tbsp melted butter/olive oil on med heat. Saute 3 cloves minced garlic and 1/4 onion diced. Add 3 lbs mussels into the skillet/pot and stir to combine with the garlic and onion. Pour in 12 oz beer and cover until the mussels are open and cooked. Stir in chopped parsley and add salt to taste. Serve immediately with a squeeze of lemon or lime, if you like.