Bacalao al Pil Pil

Ingredients

• 4 thick pieces salt cod loin with skin on, about 180g each
• 300ml extra virgin olive oil
• 6 garlic cloves, thinly sliced
• 2 dried guindilla chillies or 1 dried red chilli, sliced

Before you cook

• Soak the salt cod skin side up in cold water in the fridge for 48 hours, changing the water every 8 hours.
• Drain the cod and pat every surface completely dry with kitchen paper.
• Slice the garlic thinly and slice the chillies into rings.
• Choose a shallow earthenware cazuela or a heavy frying pan that holds the four pieces snugly.

Steps

1. Pour the olive oil into the cazuela and set it over low heat.
2. Add the sliced garlic and chilli to the cold oil.
3. Warm them gently for 4 minutes until the garlic turns pale gold, watching closely because burnt garlic will ruin the sauce.
4. Scoop the garlic and chilli out with a slotted spoon and set them on a plate.
5. Take the pan off the heat and let the oil cool for 3 minutes until it is warm rather than hot, around 70C.
6. Lay the cod pieces in the oil skin side down.
7. Return the pan to the lowest possible heat.
8. Poach for 8 minutes, keeping the oil at a bare shiver with only the occasional tiny bubble rising from the skin.
9. Turn each piece over carefully with a fish slice.
10. Poach for 4 minutes more, then lift the cod onto a warm plate and cover it loosely.
11. Tilt the pan and look for the cloudy white juices pooled beneath the clear oil, which is the gelatin you need.
12. Pour off all but about 3 tablespoons of the oil into a jug, leaving every trace of the white gelatin in the pan.
13. Let both the pan and the jug cool for 5 minutes until merely warm to the touch.
14. Grip the pan with both hands and swirl it in slow, steady circles, keeping the base flat on the worktop.
15. Keep swirling for a full minute until the gelatin and oil in the pan turn pale and creamy.
16. Dribble in the reserved oil a teaspoon at a time, swirling constantly, exactly as you would build a mayonnaise.
17. Continue until all the oil is incorporated and the sauce is thick, glossy and the colour of buttermilk.
18. If the sauce breaks and looks oily, add a tablespoon of cold water and swirl hard to bring it back.
19. Slide the cod back into the sauce skin side up and warm it through over the lowest heat for 1 minute.
20. Scatter the reserved garlic and chilli over the top and serve straight from the cazuela with bread.