I left out the red pepper flakes because I didn't have any and I added some store bought sauce for the top layer because I ran out of the sauce that the recipe called for. If I make it again I'll probably either add another can of crushed tomatoes to make more sauce or just use store bought spaghetti sauce because that'd make it so much easier.
The thing I was surprised about with this recipe was how easy it was. Seriously, all I had to do was mix the sauce ingredients together, mix the cheese ingredients together, and then layer them with uncooked noodles and spinach. Part of my resistance to making my own lasagna was because I've seen several recipes where you have to cook the lasagna noodles before adding them to the lasagna.
The cooking time of 3 - 3 1/2 hours was perfect. The noodles were cooked all the way through and the cheese on top was melted. The lasagna looked really impressive when I served it. The layers held together well, even though the cheese mixture was a little hard to spread when I was making it. As for the flavor, it was pretty good. I think it could be better with a few changes, which I'll explain below.
I gave this recipe 4 out of 5 stars for what it could be! When I make it again, which I will, I will make it even easier by using store bought spaghetti sauce because the store bought spaghetti sauce I used in the top layer had mushrooms in it and definitely added to the flavor. The other things I would do is use a little less spinach, a little more mozzarella/parmesan cheese in the cheese mixture, and probably add some ground beef because I know that Andrew's going to complain about the lack of meat when he tries it!
The best part about this recipe? It's gotten me over my fear/resistance to making homemade lasagna!