Txangurro Relleno (stuffed Spider Crab)

Boil enough sea water, or fresh water (with salt and bayleaf added), to cook the crab. Drop in crab, bring back to the boil and boil for 12 mins. Stand for 5 mins. Extract meat from crab. Put the meat into two cleaned carapaces and reserve all the debris. Heat the oil in a pan, add onion, carrot and leek, cook until tender, move to the side of the fire, add flour, paprika and crab debris. Mix well. Pour cognac over and light it. When the flames die, add wine, chilli, and tomatoes. Boil, pass it through a mouli-legumes, cook for another 20 mins and then pass it through a chinois, rubbing it through with a spoon. (From the context I guess these are sieves, but anyone got a more specific description?) Cook until reduced by half, the pour it over the crab meat and mix well. Sprinkle breadcrumbs, parsley and melted butter on top. Put into hot oven for 5 mins. The result should be a dark brown dish with the consistency of a thick soup.