"I made this last night and it was so good! I didn't know what summer squash was nor could i find it at the grocery store, so i omitted that and just added more mushrooms instead. also, as I didn't want to spend a fortune on cheese (or the time it takes to shred it), i took the lazy-man route and just added a pre-shredded italian blend (mozza, parmesan, provolone, and emmental) and it was still really good (although i can imagine how much better it would be with the smoked mozza...yum!) and still really healthy. I will definitely will make this again!