Txangurro a la donostiarra — Cook

Ingredients

2 live spider crab (txangurro), purchased live; reject any sold dead from the display
coarse sea salt, to heavily salt the cooking water
For the sofrito
1 white onion, finely chopped
3 ripe tomatoes, peeled, seeded, finely chopped
60 ml txakoli
30 ml brandy or cognac, for flambéing into the sofrito
olive oil
salt, to taste; the sofrito must not be under-seasoned
For the gratin
fine dry breadcrumbs, a thin, even layer only — sufficient to crust, not to absorb

Method

1
Bring a large pot of water to a rolling boil and season it heavily with coarse sea salt — it should taste of the sea. Lower the live crabs into the water. Cook for 15–18 minutes. Do not exceed this time: the crab will be returned to heat during the gratin stage and will tighten further. Remove the crabs and cool them in the cooking liquid.
2
Once cool enough to handle, disassemble each crab methodically. Lift the carapace free and reserve it as the service vessel. Scrape every trace of coral and interior juices from the shell into a bowl — this is the richest flavour component of the dish and nothing is discarded. Extract all white meat from the body cavities and claws. Keep the coral and juices separate from the white meat. The shell interior should come away clean.
3
Film a wide pan generously with olive oil over a low flame. Add the finely chopped onion and cook slowly, without colouring, until fully softened and sweet — allow no less than 15 minutes. Add the chopped tomato and continue cooking over low heat for a further 15 minutes or more, stirring occasionally, until the sofrito has collapsed into a dense, unified mass with no standing liquid. The sofrito must be seasoned thoroughly at this stage.
4
Add the brandy or cognac to the sofrito and flambé: tilt the pan away from you and ignite the spirit, or apply a long match. Allow the flames to die entirely before proceeding. Add the txakoli and stir through. This is where the dish lives or dies — the coral and interior juices are now added and stirred into the sofrito until fully incorporated, enriching and binding the sauce. Fold in the white crab meat. Heat gently until the mixture is just combined and warmed through; do not cook aggressively. Taste and adjust seasoning.
5
Spoon the crab mixture back into the reserved carapaces, mounding it neatly. Scatter a thin, even layer of breadcrumbs across the surface — sufficient only to form a crust. Place the filled shells under a very hot grill for 3–4 minutes. The surface should be golden and lightly crisp, not browned through; the breadcrumb is a crust, not a sponge. Serve immediately in the shell.