Tiella Barese

Ingredients

• 800 g waxy potatoes, peeled, sliced 3 mm thick
• 300 g short-grain rice, raw, unwashed
• 1 kg mussels, scrubbed, debearded, opened on the half-shell; soaked overnight in salted water with 1 tbsp flour
• 200 g cherry tomatoes, halved
• 2 medium onions, finely sliced
• 3 cloves garlic, minced
• 1 small bunch flat-leaf parsley, roughly chopped
• 80 g pecorino, finely grated
• 100 ml extra-virgin olive oil, plus extra for the pan
• 400 ml water, cold; enough to just cover the rice layer — adjust to the pan

Method

1. 1
   The night before, submerge the mussels in well-salted cold water with one tablespoon of flour. The following day, drain, scrub any remaining barnacles, remove the beards, and prise each mussel open on the half-shell, retaining all liquor. Discard any that will not open. The shells should smell of clean sea.
2. 2
   Heat the oven to 180 °C. Oil a wide terracotta or heavy metal tiella or roasting pan generously. Lay half the potato slices in a single, slightly overlapping layer across the base. The potatoes should cover the pan floor without gaps.
3. 3
   Scatter the raw rice evenly over the potato base in an even layer. Distribute the sliced onion, minced garlic, halved cherry tomatoes, and chopped parsley across the rice. Strew half the grated pecorino over the surface.
4. 4
   Arrange the mussels shell-side up across the rice layer in a single close layer, pouring over any retained mussel liquor. Scatter the remaining pecorino between and over the mussels. This is the step on which the dish lives or dies: the mussels must remain on the half-shell and be placed shell-side up so their liquor drains directly into the rice during baking — mussels removed from the shell will dry out and the rice will lack its essential brine.
5. 5
   Lay the remaining potato slices over the mussels in an overlapping layer, covering the surface as completely as possible. Drizzle the olive oil evenly and generously across the top. Pour cold water carefully around the edges and through any gaps until the rice layer is just covered — the top potato layer should not be submerged. The water level, seen from the side, should be level with the top of the rice.
6. 6
   Bake at 180 °C for approximately one hour. The dish is ready at this stage when the top potato layer is beginning to colour and a thin skewer meets no resistance when pushed through to the centre — the rice below should feel tender, not hard.
7. 7
   Raise the oven to 220 °C and bake for a further 10 minutes. The top potato layer must turn deep golden and crisped at its edges — this crust is the dish's defining texture. Remove from the oven and rest for 10 minutes before serving so the rice firms into cohesive layers.