Just a few bold ingredients give you plenty of punch in this dish fit to be served at even the finest gastro-pub. The depth of flavor from the Stout holds up well to the mussels, without overpowering them, and is accented nicely by the caramelized onions. Serve crusty baguette or rolls alongside to soak up the delicious juices.
Tips: You can double the recipe to make four servings, just be sure to use a very large pot that will fit the mussels without crowding and shake the pot gently while they cook to allow them to steam evenly. For easy entertaining, prepare the onions through step 1 up to 8 hours ahead. Cover the pot and set aside at room temperature until ready to cook the mussels. Reheat the onions over medium heat until sizzling before proceeding with step 2.