01 -
Preheat your oven to 375 degrees. Grease a 9x13 inch baking dish.
02 -
Cook the penne pasta according to package directions until al dente. Drain and set aside.
03 -
In a large skillet, brown the Italian sausage over medium heat, breaking it up as it cooks. Add the diced onion and minced garlic, cooking until the onion is translucent.
04 -
Stir in the marinara sauce, diced tomatoes, oregano, basil, salt, and pepper. Let it simmer for 5 minutes to let the flavors come together.
05 -
Add the cooked pasta to the sauce mixture in the skillet. Stir everything together so the pasta is evenly coated with sauce.
06 -
Transfer the pasta and sauce mixture to the prepared baking dish, spreading it out evenly.
07 -
Sprinkle the grated Parmesan cheese evenly over the pasta. Top with all of the shredded mozzarella cheese. Arrange the sliced pepperoni over the mozzarella - it'll look just like a pizza!
08 -
Bake for 25 to 30 minutes, until the cheese is melted, bubbly, and starting to turn golden in spots.
09 -
Let it stand for 5 minutes before serving - this helps it set up so it's easier to dish out. Serve hot and watch it disappear!