Clean Eating: Zucchini Lasagna FAIL

Well, this is my first major FAIL in Clean Eating cooking. I had to substitute eggplant for the zucchini and while it still tasted okay, the eggplant skin was tough and nearly impossible to cut. It turned out being less a lasagna and more of a stewy mess:

 

 

I would like to try this recipe again with zucchini, or, if I have to substitute with eggplant again, I'll peel the skin off first!