Heat a skillet over medium heat.

Place one tortilla in the skillet and sprinkle half of the mozzarella cheese on one half of the tortilla.

Layer pepperoni, bell pepper, and mushrooms on top of the cheese.

Sprinkle the remaining mozzarella cheese over the toppings and fold the tortilla in half.

Cook for about 3-4 minutes until the bottom is golden brown and the cheese starts to melt.

Carefully flip the quesadilla and cook for another 3-4 minutes until the other side is golden brown and the cheese is fully melted.

Remove from skillet and let it cool for a minute before cutting into wedges.

Serve with pizza sauce for dipping.