2 tbsp chipotle paste (we used Discovery, available from Waitrose)
2 tbsp chilli powder
3 tbsp soft brown sugar
2 pork tenderloin, about 500g each
coriander sprigs and warm soft tortillas (flour or corn), to serve
Place the thinly sliced onion in a bowl with juice 1 lime, half the oregano and a pinch each of salt and pepper. Set aside.
Dry-fry the whole garlic in a non-stick pan until blackened on both sides, about 8 mins, then peel. Heat the grill. Arrange the thickly sliced onion on a baking tray with the tomatoes, cut-side up. Season and grill until blackened, about 8 mins. Tip into a bowl with the garlic, chipotle paste, 1 tsp chilli powder, 1 tbsp sugar and remaining lime juice. Season and whizz in a blender until smooth. Gently heat through in a pan.
Rub the pork with the remaining chilli powder, oregano, sugar and seasoning. Grill for 5 mins each side until cooked. Serve sliced in warm tortillas with some sauce, the pickled onions and coriander.