Mix all the ingredients.
Place the mushrooms in a bowl and add a tablespoon of the fajita mix and a tablespoon of the vinegar. Also, add salt and mix.
In another bowl do the same with the chicken breasts.
Preheat two pans over high heat. Add a bit of vegetable oil to the pan and add the chicken to one pan and the mushrooms to the other. Work in batches, adding only enough to cover the base of the pans while still having some space between each piece.
For the mushrooms to become golden you need to leave them still for a couple of minutes so they can become golden. Then you stir and leave them still for another couple minutes.
For the chicken it's similar. You have to cook them on one side until cooked three-quarters of the way (you know because it starts to become white) then you flip them. Depending on the thickness of the chicken, it will need 3-5 minutes on the other side.
Cut the chicken in strips to serve.
Slice the avocado, wash the lettuce and place ricotta on the table.
Finish each fajita with a drizzle of olive oil.