*If you have not cooked the chicken yet you will want to do this first, cubed or shredded chicken will work well in this recipe.
Heat oil in a large frying pan on stove over medium to low heat, chop onions and place in frying pan, add 3 Tbsp of chicken broth and cook on stove til tender, approx 20 minutes, stir often.
While onions are cooking you can cook the pasta, boil water and cook according to package, then drain the pasta when ready.
Preheat oven to 350F
Mix chicken, pasta, onions, onion soup mix, mustard, vinegar, chicken broth, salt & pepper and 1/2 cup of cheese together in a large bowl. Spread out the mixture into a sprayed 9x13 casserole dish
Cover with foil and bake in the oven for 20 minutes, remove foil, spread remaining 1/2 cup of cheese on top and put back in the oven uncovered for 5 minutes or just enough time for the cheese to melt.
Makes 6 servings, each serving approx 7oz