Heat the oil in a frying pan over a medium heat. Add the onion and fry for 2 minutes, until softened. Add the beef strips and the Mexican spice blend, and stir-fry for 1 minute. Add the mixed beans and cook for a further 2-3 minutes until heated through.
Meanwhile, heat the tortillas according to the pack instructions. Put the soured cream, salad, couscous and grated Cheddar into individual bowls. Bring to the table with the beef mix and warmed tortillas so that everyone can make their own burritos. Fold up the base and then the sides to eat.
Cook's tip: for another delicious variation, use sliced chicken breast in place of the beef and cooked rice in place of the couscous.