Chicken Tetrazzini Casserole is a one-pot meal that saves you time in the kitchen but still tastes absolutely amazing. With juicy shredded chicken breasts, spaghetti noodles, green peas, and mushrooms, mixed together in a creamy cheese sauce for the ultimate comfort food casserole!
Heat your Instant Pot to Sauté mode until it reads "hot."
Add in the butter, garlic, and diced onion. Sauté the onion until it begins to turn translucent in color. Add in the sliced mushrooms and sauté again for 1 minute.
Turn off the Instant Pot.
Pour in the broth and if necessary, deglaze the bottom of the Instant Pot by scraping the bits of anything stuck on it.
Break the spaghetti noodles in half and then lay ⅓ of the noodles across the bottom of the pan, then another ⅓ over the top of that in a criss-cross formation. Then, add the third layer of noodles on top in another criss-cross pattern.
Do not stir.
Add the whipping cream on top and do not stir.
Add in your cubed chicken and do not stir.
Set to Manual Pressure for 4 minutes and allow for a 3-minute Natural Release, then do a quick release for the remaining pressure.
Stir the pasta and chicken together.
Add in the peas, sour cream, and cheese, stirring to combine.
Close the lid for 1 minute to heat the dish through.
Optional: Pour the Chicken Tetrazzini into a casserole baking dish and top with french fried onions. Then bake at 350 degrees for 5 minutes to crisp the top.
Notes
Storage
Storage: Keep your chicken tetrazzini in the fridge in an airtight container or tightly wrapped in plastic wrap for up to one week.
Freezing: Put the casserole in a freezer-safe container and freeze it for up to 3 months. Defrost thoroughly in the refrigerator before reheating it.
Reheating: Reheat Chicken Tetrazzini in a saucepan on the stove over medium-high heat. Add in a little broth or butter and stir almost constantly to help distribute the heat. You can also bake it covered at 350 degrees until it’s warm all the way through.