Chicken Tortellini Bake

This is a simple, easy and truly delicious casserole that even my pickiest chicken-hating daughter ate with gusto and declared the "best supper ever!". So I'm definitely making this one again. The original recipe came from "Mel's Kitchen Cafe", a favorite spot of mine to find delicious recipes. The only changes I made to the recipe were to increase it to fit my 11x15-inch casserole dish to accommodate feeding my large family, so I'm posting the changes I made here so I can make it again.

Chicken Tortellini Bake

2 (19 oz.) pkgs. frozen cheese tortellini (I used the Wal-Mart store brand)
2 TBSP. olive oil
3 cups chicken cut up into bite size pieces
1 small onion, chopped
1/4 cup flour
2 cups chicken broth
1 lb. sliced fresh mushrooms (opt.)
1 1/2 cups sour cream (reg. or lite)
3-4 cups shredded cheese (I used a mixture of Mozzarella, Cheddar and some Parmesan)

Bring a large pot of water to boil and cook tortellini according to package directions. Drain and set aside. Heat the oil in a large non-stick skillet over medium heat. Brown the chicken for 1-2 minutes and add the onions and mushrooms, cooking until chicken is done and mushrooms are golden brown. Sprinkle flour over mixture and stir to combine. Cook for 1-2 minutes. Add chicken broth and stir until thickened. Mix in sour cream until mixture is creamy and slightly thickened. Spray a 11X15 pan with cooking spray. Pour tortellini in bottom of pan. Sprinkle half the cheese over tortellini. Put cooked chicken/sauce mixture on top and sprinkle remaining cheese over the top. Bake covered with tin foil at 350* F for 30 minutes, uncover and bake for additional 15 minutes until bubbly and golden brown around the edges.
Makes about 10-12 servings.

**This can be made ahead of time and chilled in the fridge for the day until your ready to bake it, and it still tastes great:)