Lay two tortillas flat on a clean surface. Spread about ¼ cup of pizza sauce evenly over each tortilla, leaving a small border around the edges.
Sprinkle ½ cup of mozzarella over the sauce on each tortilla, then layer on your pepperoni and bell pepper. Dust with garlic powder and Italian seasoning.
Top each loaded tortilla with a second tortilla and press down gently.
Heat a large skillet or griddle over medium heat and brush with a little olive oil or butter.
Place one quesadilla in the skillet and cook for 3–4 minutes until the bottom is golden brown and crispy.
Carefully flip using a wide spatula and cook another 3–4 minutes on the second side.
Remove from the pan, let it rest for 1 minute, then slice into wedges. Repeat with the second quesadilla.
Serve with warm pizza sauce on the side for dipping.