Preheat the oven to 375°F. Spray a 9x13 baking dish with nonstick spray and set aside.

Bring a large pot of salted water to a boil.

While you are waiting for the water to boil, heat a large skillet over medium-high heat.

Add the Italian Sausage and cook, breaking it up until it's completely cooked through.

Add the garlic and saute just until fragrant, about 1-2 minutes. Be sure not to burn the garlic.

Pour in the beef stock and scrape the browned bits from the bottom of the skillet. Let it simmer for a minute.

Pour in the Worcestershire sauce, marinara sauce, garlic powder, oregano, and basil. Mix to combine. Let it simmer on low while you boil the pasta.

Add the pasta to the boiling water and cook until al dente.

Combine the cooked pasta, sauce mixture, half of the pepperoni, and half of the mozzarella. Mix until it's fully combined.

Pour the mixture into the 9x13 baking dish.

Sprinkle the top of the pasta with the remaining mozzarella, parmesan, and pepperonis. Sprinkle the top with red pepper flakes if using.

Cover and bake for 10 minutes. Remove the cover and bake an additional 15 minutes uncovered.

Remove from the oven and allow it to cool for 10 minutes before serving.