Preheat oven to 350 degrees F. Grease a deep 9x13 inch casserole dish generously with nonstick spray, including the sides.

Open the first can of biscuits and use scissors to cut each biscuit into sixths. Layer the pieces across the bottom of the prepared casserole dish.

Take half the pepperoni package and cut each slice into quarters using scissors. Spread evenly over the biscuit layer.

Add 1 and a half cups of shredded mozzarella over the pepperoni. Pour one full jar of pizza sauce evenly over the top and sprinkle with half a tablespoon of Italian seasoning.

Add the second can of cut biscuits on top, followed by the remaining cut pepperoni and half of the second jar of pizza sauce. Sprinkle with the remaining half tablespoon of Italian seasoning. Reserve the rest of the second jar for serving.

Sprinkle 1 to 2 cups of mozzarella cheese over the top. Grate 3 tablespoons of Parmesan cheese over everything.

Spray a sheet of foil with nonstick spray on the underside and cover the dish tightly, sprayed side down. Place the casserole dish on a large baking sheet to catch overflow. Bake covered at 350 degrees F for 60 minutes.

Uncover and continue baking for 10 to 15 more minutes until the top is golden and bubbly. Test biscuits in the center with a toothpick. If not fully cooked, cover and return to oven in 5-minute increments until done.

Serve immediately with the remaining pizza sauce warmed in the microwave.