Fry mushrooms, green pepper and onion and cook about four minutes then drain and set aside.
Whisk eggs and milk until blended. Add ham, vegetable mixture, spinach, salt and pepper.
Divide mixture equally between four 8-ounce mason jars.
Place rack in your Instant Pot and add one cup of water. Place jars on rack.
Cook on high pressure 10 minutes. Allow pressure to decrease on its own.