Do not remove the mussel beards until just before cooking. Removing this thread will speed the decay of the mussels. The mussels can be steamed in advance and the dish assembled and chilled. To serve, warm the mussels under a broiler to brown the crust.
2 lb (about 1 kg) mussels
¼ cup (60 mL) white wine
1 Tbsp (15 mL) grainy mustard
1 Tbsp (15 mL) maple syrup
1 Tbsp (15 mL) miso
1 Tbsp (15 mL) mayonnaise
¼ cup (60 mL) panko crumbs
Place the mussels in a large bowl and rinse quickly with cold water. Pull off any threads attached to the side of the shell (the beards). Drain and set aside.
Place a large pot over medium-high heat. Add the wine and bring to a boil. Add the mussels and cover the pot with a lid; cook for 5 minutes, shaking the pot occasionally. When the mussels have just opened and are still plump, remove them from the pot and set aside. Reduce the juice over high heat until about 2 tablespoons (30 mL) of rich liquid is left (about 5 minutes).
Preheat the oven to broil.
In a small bowl, combine the mussel juice, mustard, maple syrup, miso, and mayonnaise to create a paste. Peel back the shell of a mussel (discard the top) and spread a little of the paste on top of the flesh. Sprinkle with breadcrumbs and place on a baking tray. Repeat with the remaining mussels. Place under the broiler until golden. Serve warm.
SERVES 4–6