Fill a large pot with water, salt well, and bring to a boil.  Cook pasta according to instructions on box. 

Cook the sausage (casings removed), breaking it up into crumbles as it cooks.  Once it is cooked through, remove from pan and set aside. 

Using the same pan you used for sausage, add minced garlic and chopped onion and cook for 1-2 minutes.  

Add chicken broth to the pan and scrap up any bits off the bottom of the pan.  Add the dijon mustard and flour and stir well. 

Add the chopped sun-dried tomatoes and the heavy cream to the pan.  Let it cook for a few minutes until it begins to bubble and thicken. 

Add the sausage back to the pan. 

Add the spinach large handfuls at a time, stirring between handfuls. 

Add 1/2 cup of grated Parmesan cheese to the sauce. 

Using a slotted spoon, add the cooked pasta to the sauce.  You don't have to drain the pasta - if a little of the salty pasta water gets into the sauce, it only makes it taste better!  Add as much pasta as you prefer.  

Taste and season with salt and pepper as needed. 

Serve in pasta bowls and top each bowl with a sprinkle of extra Parmesan cheese.