If baking the chimichangas, heat the oven to 200C/180C fan/gas 6.
Heat 1 tbsp of the oil in a frying pan or skillet pan on a medium heat, add the chicken thigh fillets and fry for 6 to 8 minutes on each side until cooked through, then remove from the pan and set aside. Add another tbsp of the oil to the pan, then the onion and red pepper and cook until softened, about 5 minutes.
Shred or cut chicken into small pieces and put in a bowl with the cooked onions and peppers, chillies, cheese and spices, season and mix well.
Heat the tortillas briefly in a dry frying pan for a few seconds on each side to make them a little more pliable, or heat in a microwave. Spoon a layer of the refried beans (if using) into the centre of each tortilla, then spoon some of the chicken mixture on top. Repeat so all the wraps and filling are used up.
Roll up the chimichangas – fold the bottom over the filling, fold the sides in, then roll away from you so all the filling is sealed in.
To bake in the oven - place the chimichangas on an oiled baking sheet and brush lightly with more oil. Bake until golden, about 20 to 25 minutes.
Or to fry them - heat a heavy-based frying pan over a medium heat. Once hot, add the 60ml oil to the pan and place the chimichangas seam-side down. Turn gently every few seconds until lightly golden on all sides and the filling has heated through.
While they cook, make the smoky enchilada sauce (instructions below). If you’ve made the enchilada sauce ahead, it can be reheated now in a small pan. Spoon some enchilada sauce on a plate, lay the chimichanga on top, and top with sour cream, a little more cheese and some coriander.