In large skillet over medium heat, cook the sausage until seared and done. Remove from skillet and set aside.
In same skillet, add the chopped onions. Cook until translucent, about 3-4 minutes. If the pan seems dry, add a drizzle of olive oil.
Add the minced garlic and saute 1-2 minutes until fragrant.
Stir in chicken broth, deglazing the pan, scraping those delicious bits stuck to the pan.
Add the diced tomatoes with juice and heavy cream.
Return the sausage to the skillet and combine.
Season with salt and pepper. (I didn't need to use any salt as the sausage was salty enough).
Bring to a gentle boil, then reduce heat and simmer for 15-20 minutes until the sauce thickens.
While the sauce simmers, cook the pasta according to package directions until al dente. Drain.
Stir in the Parmesan cheese until melted.
Add spinach and stir until wilted, this will only take a few minutes.
Serve the sauce over warm pasta, topping with extra Parmesan if desired.