Tiella Barese: Riso, Patate e Cozze (Italian Rice-Stuffed Mussels)

Ingredients

• 16 black mussels, scrubbed (about 450g)
• Extra virgin olive oil, for drizzling
• ½ brown onion, finely diced
• 2 garlic cloves, crushed
• 100g arborio rice (3½oz)
• 250g Dutch cream potato, peeled and finely sliced (9oz)
• 100g cherry or grape tomatoes, cut into quarters or eighths (3½oz)
• Handful parsley leaves and fine stems, finely sliced (about 15g/½oz)
• 35g freshly grated Pecorino Romano (1¼oz)
• Salt flakes and freshly ground black pepper, to taste