- STEP 1
Scrub the mussels really well and remove the beards. Discard any with damaged shells and those that don’t shut tight when tapped on the edge of the sink. Rinse well. Put all the mussels in a medium saucepan and cover with a tight-fitting lid. Place over a high heat and cook for 2 mins, shaking the pan halfway, until all the shells have steamed open but the mussels are only just cooked. Discard any that don’t open. Tip into a colander and leave to cool.
- STEP 2
Tear the bread into rough pieces, put in a food processor and blend into crumbs. Rub the walnuts between your hands to remove some of the papery skins. Add the walnuts, butter, garlic, lemon juice and Parmesan to the crumbs. Season with a good pinch of salt and ground black pepper. Blitz until all the ingredients begin to blend. Add the herbs to the stuffing and blend until combined with the butter.
- STEP 3
Heat the grill to its hottest setting. Take each mussel and carefully prise off one half of each shell. Drain away any excess liquid. Place the mussels in their remaining shells on a small baking tray. Using a teaspoon and your finger, divide the stuffing mixture between each mussel shell, making sure the mussel itself is fully covered. Place the tray fairly close to the grill and cook for about 2 mins until the stuffing is pale golden brown and the mussels are hot and surrounded by the melted butter. Transfer the shells to 2 plates and eat straight away.