To make the salsa, combine the red onions, tomatoes, vinegar, half the parsley and half the oil, then season to taste. Toss the avocado slices with a splash of the lime juice, and set aside.

Heat the remaining oil in a non-stick pan over a medium-high heat and cook the onions for 5 mins, then stir in the grated carrot and mushrooms, and cook for 3-5 mins more until lightly browned. Mix in the tomato purée and spices, and cook for 3-5 mins until the purée turns dark red. Pour in 200ml water, the kidney beans, corn and remaining parsley. Cook for 5-6 mins until the mixture has reduced, thickened and is heated through. Season with the cayenne pepper and salt and pepper to taste.

Warm the tortillas following pack instructions and reheat the rice until piping hot. Assemble the burritos by topping the tortillas with the lettuce, vegetable filling and rice. Dot over the avocado slices and soured cream, then fold in one side of the tortillas and roll up. Serve warm, with the salsa on the side.