01 - Preheat oven to 350°F and grease a 9x13-inch baking dish with cooking spray or butter.
02 - Cut refrigerated biscuit dough into 1-inch pieces and scatter evenly in the prepared baking dish.
03 - In a medium bowl, toss biscuit pieces with 1 cup of pizza sauce and half the mozzarella cheese until evenly coated.
04 - Spread the coated biscuit pieces evenly in the dish, then pour the remaining pizza sauce over the top.
05 - Layer pepperoni, black olives, and bell peppers over the biscuit base.
06 - Sprinkle remaining mozzarella and cheddar cheese evenly over the toppings.
07 - Season with Italian herbs, garlic powder, crushed red pepper flakes (if using), salt, and black pepper.
08 - Bake uncovered for 30-35 minutes until biscuits are puffed and golden brown and cheese is bubbly.
09 - Let the casserole rest for 5 minutes before serving to allow the cheese to set.