Add bacon, garlic powder, cream cheese, chopped cheddar cheese, grated parmesan cheese, pepper, finely chopped scallion heads, paprika, and salt to a mixing bowl.
Mix everything well with a spatula.
Gently remove the mushrooms' stems using your hands.
Stuff the filling into the mushrooms' caps. Press the filling so that it fills up the mushrooms.
Preheat the air fryer to 400°F for about 5 minutes. Spray cooking oil on the air fryer basket and put the mushrooms in.
Reduce the temperature to 350°F and air fry the mushrooms for 6 minutes.
After 6 minutes, sprinkle the mushrooms with shredded cheddar cheese (optional). Cook the mushrooms for another 2 minutes to melt the cheese.
Once the mushrooms are perfectly cooked, sprinkle them with scallions.
Let them rest for about 5 minutes, and enjoy!