This was so tasty! I'd never cooked with Italian sausage before now, but it had a sweeter flavor than what I was used to (even though I got the hot Italian sausage). I think this was the closest I've ever gotten to a 30 minute meal. It made a lot for just the two of us, so I can tell you that it was still great reheated for lunch. I'll make this again.
Italian Sausage Pasta
1 lb penne pasta
1 lb hot or sweet Italian sausage, removed from its casing
1/2 tsp red pepper flakes
2 Tbsp olive oil
2 (14oz) cans diced tomatoes, drained
1/2 cup diced onion
3 cloves garlic, minced
1 cup reserved pasta water
Bring a large pot of salted water to a boil. Cook pasta in boiling water for 8-10 minutes and drain.
Heat oil in a large, deep skillet over medium heat. Cook sausage and pepper flakes until sausage is evenly browned. Stir in onion and garlic, and cook until onion is tender. Stir in tomatoes, and cook for 8-10 minutes. Stir in pasta and cup of pasta water, and heat through. Sprinkle with Parmesan cheese.