In a medium mixing bowl, blend together egg whites, roasted red pepper, spinach, Monterey Jack cheese and salt using an immersion blender or whisking thoroughly.
Generously grease silicon egg bite mold with cooking oil or butter. Pour egg mixture into each cup filling just below the top of each cup.
Add water to the Instapot. Place egg bite mold on top of the Instapot trivet and carefully lower the trivet and egg bite mold into the Instapot. Lay a sheet of foil loosely over top of the egg bites to prevent water from dripping into egg bites.
Close lid and set pressure value to "Steaming." Use the manual setting by pressing the "Pressure Cook" button and set the Pressure Level to Low Pressure. Set cook time using the + or - buttons to 8 minutes. Allow about 10 minutes for pressure to build then let cook for 8 minutes. When done, let pressure naturally release for about 4-5 minutes. Release the value completely and when pin drops, open the lid. Remove foil careful to not spill water onto the egg bites. Turn over egg mold onto a plate and squeeze too loosen each egg bite from the mold.
Enjoy fresh or refrigerate or freeze them, then reheat using the microwave before serving.