This recipe requires the “pot in pot” method of pressure cooking. If you do not have a oven-proof container that will fit inside the inner liner of your pressure cooker, create a sling using the trivet and aluminum foil.
Pour water into the pressure cooker and place the trivet inside. Rest the “pot in pot” or sling on top of the trivet.
Coat tilapia fillets with cajun seasoning on all sides. Place the fish in the inner pot or sling, stacking the fish if needed.
Close and set the valve to sealing. Set the pressure cooker to manual or pressure cook on high for 2 minutes. Quick release the pressure. Check the inner temperature of the fish, verifying it has reached a minimum of 145 degrees.
Carefully remove the tilapia from the pressure cooker and keep it warm. Turn off the pressure cooker and pour out the water. Place the pot back inside the pressure cooker and turn on the saute function.
When the temperature reaches “hot,” melt the butter. Stir in the cream, garlic powder, black pepper, and Parmesan cheese. Whisk until the cheese has melted, about 1 minute. Turn off the pressure cooker. The Alfredo sauce will thicken as it cools. Serve over tilapia.