4medium zucchinisliced 1/8" thick. (UPDATE: Since some readers are saying that this lasagna become a little soupy I made this lasagna again but this time I grilled the zucchini slices before I put on the slow cooker. It helped to draw out some moisture!
Place some of the ricotta cheese mixture and top with the mozzarella cheese.
Repeat the layers until all your ingredients are all used up.
Top the lasagna with mozzarella and Parmesan cheese.
Cover and cook on high for 3 to 4 hours.
Turn off the slow cooker and let stand for about 1 hours. (UPDATE: Since some readers said the lasagna became a little soupy, I made it again and I let it stand for about 3 HOURS before serving. I found it was great because the liquid absorbed much more - Please, do not forget this step).