Step 1

Heat oven to 160C/140C fan/gas Take the pork out of the fridge and allow to come to room temperature. Then put in a roasting tin and roast for 15 mins or until completely warmed through.

Step 2

Heat a non-stick frying pan over a medium heat. Brush the lime halves with 1 /2 tbsp oil and put them, cut-side down, in the pan. Leave to caramelise for a few mins, then set aside. Add the olive oil to the pan, followed by the cumin seeds and ground cumin, and allow to sizzle. Add half the onion, the garlic and coriander stalks, and season. Cook for 5-8 mins until soft and fragrant.

Step 3

Add the black beans and a splash of juice from their can, and cook, stirring, for about 8 mins until thickened. Squeeze in the juice from half a caramelised lime and stir to combine.

Step 4

Meanwhile, slice the avocado, squeeze over the juice of half a caramelised lime and season. Char the tortillas in a dry frying pan, or wrap in foil and put in the oven for a few mins to warm through. Serve them topped with the black beans, pork, onion, avocado and coriander leaves, with lime wedges on the side for squeezing over.