Add a drizzle of olive oil to a pan, and add onion, saute until almost soft, then add the spinach and continue to saute.
Slice the sausage and add it to the pan and let sausage brown, and heat through.
Add the can of tomatoes drained.
By this time the noodles should be cooked, drain and add to the pan with the sausage.
In the pan you cooked the noodles, melt two tablespoons of butter. Add two tablespoons of flour and let cook until bubbly. Add chicken broth, and cook until thickened. Then add cheese, and cook until melted.