Step 1

Preheat the oven to 375ºF and spray a 9×13-inch casserole dish with non-stick cooking spray

Step 2

Heat a large dutch oven over medium/high heat and add olive oil, onion, garlic, celery, carrots, mushrooms, garlic powder, and onion powder to the dutch oven and cook for 5 minutes

Step 3

Sprinkle flour over the vegetables and use a wooden spoon to mix the flour with all of the vegetables until the flour absorbs all of the excess liquid in the pot

Step 4

Turn heat to medium and slowly add the milk to the pot, stirring constantly until milk thickens and remove dutch oven from heat

Step 5

Add in cooked rice, frozen peas, and chicken to the greased casserole dish and mix

Step 6

Next add the contents of the dutch oven to the casserole dish and mix again

Step 7

Add the broth, salt and pepper to the casserole dish and mix until everything is combined

Step 8

Cover the casserole dish with tin foil and place in the oven at 375ºF for 30 minutes

Step 9

At 30 minutes, remove the tin foil and bake for an additional 30 minutes (I like to mix around the contents and stir every 10 minutes or so)

Step 10

Remove casserole dish from the oven and let sit for at least 10 minutes to fully thicken (it’s okay if there is still liquid – it keeps the dish moist especially for leftovers)

Step 11

Serve while warm!