In a large bowl, mix the blueberry muffin mix, egg, and water according to the package instructions. Gently fold in the blueberries from the can (or any additional fresh blueberries you might want to add).

Lightly spray the egg mold or silicone molds with non-stick cooking spray to ensure the muffins don’t stick.

Pour the muffin batter into the molds, filling each about three-quarters full to allow room for the muffins to rise.

Pour 1 1/2 cups of water into the bottom of the Instant Pot. Place the trivet inside the pot, and carefully lower the filled egg mold onto the trivet.

Secure the Instant Pot lid and set the valve to the sealing position. Select the "Pressure Cook" or "Manual" setting, and cook on high pressure for 10 minutes.

After the cooking time is complete, allow a natural pressure release for 5 minutes, then carefully do a quick release to release any remaining pressure.

Carefully remove the egg mold from the Instant Pot using tongs or oven mitts. Let the muffins cool for a few minutes before removing them from the mold.