Preheat oven to 350°F and butter a 9x13" baking dish. Set baking dish aside.

Bring a large pot of salted water to a boil. Boil ziti about a minute less than the package directions for al dente. Drain and set aside (stirring occasionally to prevent it sticking together).

Heat a large deep skillet over MED HIGH heat. Once hot, add the olive oil and sausage and cook, crumbling as it browns, for about 5-6 minutes, until cooked through. Drain.

Add the cooked sausage back to the skillet, then add garlic and stir well.

Pour in marinara sauce and add the red pepper flakes. Stir well to combine, then lower the heat to keep the sauce at a simmer.

Simmer for about 10 minutes, until heated through and slightly thickened.

Remove skillet from the heat, then stir in the cooked pasta.

Transfer half of the ziti mixture to the prepared baking dish, then top with half of the mozzarella and romano cheeses.

Top with the remaining ziti mixture, and remaining mozzarella and romano cheeses.

Bake in preheated oven, uncovered, for 20 minutes, or until hot and bubbly.

Remove from oven and set aside for 5-10 minutes, then sprinkle with parsley and serve!