Preheat oven to 375* and lightly spray/grease a 9x13 baking dish. Set aside
Boil pasta according to package directions. Set aside.
In a large saute pan over medium-high heat, cook Italian sausage and diced onion until sausage is crumbly and almost cooked through. Add in minced garlic and salt and pepper to taste. Continue cooking for 1-3 minutes until sausage is cooked through.
To your meat mixture, add marinara sauce, diced tomatoes, and Italian seasoning. Reduce heat and simmer for about 5 minutes.
Remove sauce from heat and add cooked pasta into sauce, tossing well.
Pour pasta mixture into prepared 9x13 pan and top evenly with mozzarella and parmesan cheeses.
Bake in 375* oven for approx 25-30 minutes or until cheeses are melted and pasta is hot and bubbly. Remove from oven. Serve and ENJOY!
NOTE: if cooking it straight out of refrigerator, add a few minutes to your cook time.
