In a large skillet, heat the olive oil over medium high heat. Once hot, add the garlic and saute for a minute, to release the oils and fragrance. Add the ground beef and cook until no longer pink, breaking up the meat as it cooks, around 5 minutes. Sprinkle with the salt and pepper.
When the beef is around 90% browned, add 1/2 cup of the pepperoni and stir thoroughly to combine. Drain excess fat.
Stir in the pasta sauce, water, and oregano, followed by the elbow macaroni. Bring to a boil.
Reduce heat to low and allow to simmer for 15 minutes, or until the macaroni is tender.
Cover the pasta with the mozzarella cheese, sprinkle with the remaining pepperoni, cover, and allow to melt for 2-3 minutes. Remove from heat, sprinkle with Italian parsley and serve immediately!