Though commonly thought a hazard, cooked mussels that haven't opened can be perfectly fine if they smell bright and clean and are properly cooked.
Extra virgin olive oil
Breadcrumbs - 2 thin slices sourdough (crusts removed), whizzed in a processor
Freshly ground black pepper
200ml dry white wine
1.5kg mussels, scrubbed and de-bearded
4 cloves garlic, sliced
250g quality small macaroni or tubetti, cooked al dente
3/4 cup freshly podded peas, smashed lightly in a mortar and pestle
1. In a little oil, fry the breadcrumbs until golden, season and crush in a mortar and pestle to a rough powder.
2. In a large pot, bring the wine to the boil, tip in the mussels, cover and cook for a few minutes, shaking the pot once or twice. Stir the mussels through so they cook evenly - you can remove cooked mussels to make room to finish the cooking more evenly. Once the mussels are nice and plump, take off the heat, strain and reserve the liquid. Remove half the mussels from their shells and keep the others on the half-shell.
3. In a large pot or saute pan, add a splash of oil and fry the garlic until fragrant and taking on some colour. Add the mussel liquid and bring to the boil, then reduce over a high heat for a couple of minutes. Add the cream and a few grinds of pepper and boil for another minute. Add the pasta and mussels and bring back to a simmer. Stir through the peas and cook for 30 seconds. Squeeze in the lemon, check the seasoning (you probably won't need any extra salt as the mussels are quite salty), scatter over the breadcrumbs and serve.