Prietas

Step 1: Soak 2 m natural pork casings in cold water for 30 minutes, then run cold water through them to rinse the inside.

Step 2: Cook 10 ½ oz pork back fat in a wide pan over a low heat until it starts to melt, then add 3 onions and cook gently until very soft but not brown. Cool completely.

Step 3: Strain 4 ¼ cups fresh pork blood through a sieve into a big bowl and stir in the onion and fat, 2 tsp ground cumin, 2 tsp dried oregano, 1 tsp sweet paprika, 1 tbsp salt and 1 tsp black pepper.

Step 4: Tie a knot in one end of a casing. Using a wide funnel, fill it three quarters full with the mixture, then tie off links about 15 cm long with kitchen string, leaving some slack.

Step 5: Heat a big pan of water to 176°F (small bubbles at the bottom, no boiling). Lower the prietas in and poach, turning gently. Prick any that float with a needle to release air.

Step 6: Check one: it should feel firm and release clear brown juice, with no red blood, when pricked (160°F inside). Lift out and cool.

Step 7: Keep chilled and eat within 3 days. To serve, grill over a medium heat or fry, turning, until the skins are crisp and the inside is hot right through.