Mix the onion, tomato, red pepper and mushrooms with the balsamic vinegar, extra virgin olive oil and the mint sauce. Season with salt and pepper.
Add 1/4 of the mix to the middle of a wrap leaving a small gap at the bottom, then sprinkle 1/4 of the grated cheese over the top.
Fold the wrap at the bottom and bring both sides in together so its tightly wrapped with no gap left at the bottom, this will prevent the mix all falling out whilst its being grilled. Repeat with the remaining three wraps.
If possible use a George Foreman® grill to cook the wraps, if not place in the oven for 3-4 minutes on a high heat.