Au gratin Chicken Casserole

I was looking around the house for something to eat, and was tired of the same ol' thing.  So, I pulled a couple of boxes of Au gratin potatoes. I looked in the freezer and found two boneless skinless chicken breasts. I was thinking, what do I have to lose, so this is the recipe I came up with.

Ingredients:

2 boxes Au gratin Potatoes
Water (required amount from box, plus 1/2 cup extra)
Milk (required amount from box, plus 1/4 cup extra)
Butter (required amount from box, plus 1tbsp extra)
2 Boneless/Skinless Chicken Breasts
1 tsp Cornstarch
1 cup Broccoli (optional)
1 cup of 1/4 cut Mushrooms (optional)
1 cup of crumbled Georgia Ritz Crackers (optional)

• Take a three court sauce pan and put your required amount of water, milk, cornstarch, and powdered cheese sauce in the pot. Use a whisk to mix it up, make sure there are no clumps. Bring to a boil.
• Cut chicken into 2 inch medallions 
• Add chicken and optional veggies, boil for 5 minutes, then add potatoes, stir in and mix well.
• Pour mixture into a 9x13 cake pan, bake according to directions
• Ten minutes before it is done, pull it out of the oven and sprinkle cracker crumbs on top and put back into the oven for the remainder of time.