This is am amazing one-pot dish that is sure to please your whole family and it's even worthy enough for guests!
Turn Instant Pot to Saute. When hot, melt butter. Add onion and cook until soft, about 4 to 5 minutes. Add garlic and cook 1 more minute.
Stir in rice, mushrooms and chicken broth (or for extra flavor, you could use 1/2 cup white wine with 3 1/2 cups chicken broth). Seal Instant Pot and set to Manual, High Pressure for 10 minutes and then quickly release the pressure valve. Leave Instant Pot setting on warm.
Stir in raw shrimp (if using), spinach, parmesan cheese and remaining seasonings. Continue stirring on warm to wilt spinach and cook shrimp thoroughly, about 5 minutes.
Serve with a side salad.