Steam green beans in the Instant Pot in a steamer basket with 1 cup of water for 1 minute. Manually release the pressure when it is done.

Drain and rinse the green beans with cold water to stop cooking. The total time to get to pressure and release for frozen green beans was 18 minutes in an 8qt Instant Pot.

Empty water from the Instant Pot Pan.

Turn the Instant Pot to Saute mode. Heat the butter and oil in the pan then add thinly sliced onions. Add salt and pepper. Saute onions until they are golden brown and starting to crisp. Remove the onions from the Instant Pot pan and set aside.

Add mushrooms to the remaining oil and cook through then add garlic and stir it for about one minute or until aromatic. Add softened cream cheese, broth, and cream to the pan. Stir into a sauce. Add salt and pepper. Return green beans and combine thoroughly. Add ½ of the cheese and mix it in.

Place green bean casserole in a casserole dish, then top with the remaining 1/2 cup of cheese and the fried onions.

Broil the casserole for 3-4 minutes. (If you don't have access to an oven, simply make sure all of the cheese melts on the green bean casserole. It wont be browned and bubbly on top but it will still taste amazing!)