Chipotles en adobo

Step 1: Wipe 2 ⅛ oz dried chipotle mora chillies with a damp cloth and make a small slit in each. Stem and seed 1 dried ancho chilli.

Step 2: Heat a dry heavy frying pan over a medium heat. Toast the ancho for 10–15 seconds a side until it smells fragrant and blisters slightly, then the chipotles for about 20 seconds, turning them. Do not let them smoke or blacken.

Step 3: Cover both with 2 cups hot water and soak for 20 minutes, weighted with a plate, until soft and plump. Keep the soaking water.

Step 4: Meanwhile, roast 10 ½ oz ripe tomatoes, ½ white onion and 4 garlic cloves on the dry pan over a medium-high heat for about 10 minutes, turning, until blistered and blackened in spots. Peel the garlic.

Step 5: Blend the tomatoes, onion, garlic, ancho, ¼ cup cider vinegar (5% acidity), 1 tsp dried Mexican oregano, ½ tsp dried thyme and 250 ml of the soaking water until very smooth.

Step 6: Heat 1 tbsp vegetable oil in a heavy saucepan over a medium-high heat, pour in the sauce (it will spit) and fry for 5 minutes, stirring, until it darkens to brick red.

Step 7: Add the chipotles, the remaining vinegar and soaking water, 1 ¾ oz piloncillo, 1 ½ tsp salt and 2 bay leaves. Simmer over a low heat, partly covered, for 30 minutes, stirring now and then, until the chillies are very soft and the sauce is thick and glossy enough to coat a spoon.

Step 8: Cool completely, then spoon into a clean, dry jar (washed hot and dried 10 minutes in a 250°F oven), pressing the chillies under the sauce. Keep in the fridge for up to 1 month or freeze for 6 months; do not store at room temperature. Discard if mould, fizzing or an off smell appears.