4 pasilla chillies, seeds and stalks removed
8 guajillo chillies, seeds and stalks removed
handful coriander stalks, finely chopped
2 garlic cloves, unpeeled
½ onion, skin on
500g/1lb 1½oz ripe vine tomatoes
freshly ground black pepper
¼ tsp ground cloves
¼ tsp cocoa powder
1 tsp cumin seeds, toasted and ground in a pestle and mortar
½ tsp dried oregano
salt, to taste
1 tbsp sunflower oil
1 tsp cider vinegar
150ml/5fl oz cola
1 orange, juice only