Preheat oven to 350°F. Lightly coat the inside of a 3 quart casserole dish with olive oil (or other cooking oil).

Cook pasta according to package instructions. Drain and return to the pot or place in a large bowl.

While the pasta is cooking, brown ground beef in a medium saucepan. Break it up with a spoon or spatula while browning to crumble it. Drain grease from beef and return to saucepan.

Add marinara sauce to the beef and stir to combine. Bring to a simmer over medium heat.

Pour meat sauce over cooked pasta. Add most of the pepperoni, reserving some slices for the top. Stir until combined. Transfer mixture to prepared casserole dish and spread evenly in the dish.

Sprinkle mozzarella cheese evenly over pasta mixture. Sprinkle parmesan over mozzarella. Place remaining slices of pepperoni on top.

Bake for 25 to 30 minutes, or until it begins to bubble and the cheese has melted and is lightly brown on the edges.