Cut tops off of peppers save the ring around the stem to use in filling. Wash and drain the inside. Now take the saved tops along with the onioun,garlic,and Mushrooms chop all into small cubes. Add 2 table spoons Olive oil heat and saute untill tender.Add you spinch at this time. Cut Chicken into bite size small chunks and add to veggies. Continue to saute untill chicken is cooked all the way through. While you are doing this stage add your choice of seasons.
Set aside your saute, make your stove top according to directions on box, subtracting 1/4 cup water. After you have made the stuffing add veggie and chicken mixture. Set aside to cool enough to handle.
After mixture is cooled stuff into pepper shells packing firmly but not so hard you crack the pepper. Take baking dish and spray with non stick spray, set stuffed peppers into dish. When ready bake for 15 min. At 400. then remove.
Last step. Mix Mayo with the shreded cheese. Chop the small tomato into small cubes mix into the Mayo and cheese mix spreed onto the top of the peppers and put back into the oven for 10 min or untill topping is light brown.