Preheat your oven to 375°F.
Cook the penne pasta according to package directions, aiming for an al-dente texture.
In a separate pan, sauté the onions and garlic in olive oil until translucent.
Add the choice of meat or vegetarian substitute, cooking until browned.
Stir in the pasta sauce, then season with salt, pepper, and Italian seasoning.
In a 9x13-inch baking dish, spread a thin layer of the meat sauce on the bottom.
Layer half of the cooked penne over the sauce, then sprinkle half of the mozzarella and Parmesan cheeses on top of the pasta.
Repeat the layering process with the remaining penne and cheeses.
Cover the dish with foil and bake for 20-25 minutes.
Remove the foil and continue baking for an additional 5-10 minutes, or until the cheese becomes golden and bubbly.
Garnish with fresh parsley before serving.