Bring a large pot of water to a boil
Once boiling, generously season with salt and let it return to a boil
Meanwhile, in a large skillet remove sausage from casings (I make a slit down the middle making it easier to remove)
Cook sausage breaking it up with a spoon until it is fully cooked (about 6 minutes)
Add pasta to the boiling water and cook 1 minute less than package instructions (al dente!)
Roughly chop spinach and set aside. Dice bell pepper and add to sausage skillet, cooking for another 3 minutes
Add jar of marinara sauce to skillet and stir
Drain pasta and add to skillet with sauce. Stir in chopped spinach
Top with shredded Parmesan cheese and serve!
Store leftovers in the fridge in an airtight container for up to 4 days