I didn't use the red pepper flakes, and we did put in half again as much parmesan cheese as this called for and a little extra minced garlic. Those were the only changes we made. This got 2 thumbs up from my old man, and I'm sadly looking at my empty plate. This was so delicious. I want more, and I already ate 2 pork chops. Don't skimp on the spinach. I don't think this would work anywhere near as well without both the spinach and the mushrooms. In fact, I think it could have done with more mushrooms, but then again, I love mushrooms. I'm definitely adding this to my go-to dinners.