Italian Sausage and Spinach Lasagna

Our dear friends just moved into a new home and while they have been busy painting, unpacking, and doing yard work, they haven't had a lot of time for cooking. I made this big pan of lasagna to help them out. Since they have been working so hard I decided to make this lasagna a little more hearty than I normally cook... they needed the calories since they were burning them off so quickly. I used