Here is another gluten free recipe, and it's also vegetarian. Could be vegan, if you don't add cheese. Which brings me to my first comment about taste--but wait, lemme 'splain the dish first.
This is more of an assembly dish than anything else. The instructions say the difficulty level is intermediate, but I beg to differ. Polenta Lasagna has been my most successful dish thus far, which means it MUST be for the beginner. The only part that made me feel like I was "cooking" rather than just putting together this dish making was the polenta. The recipe calls for 25 minutes of stirring as it thickens and by golly I had my wooden spoon in motion for 25 minutes.
The directions also say you should chill the polenta for an hour, "but longer is better". It's a good thing, too, because I was unable to finish the dish last night, and it kept very well for 24 hours (covered). The filling between the polenta "noodles" is just mushrooms, zucchini and yellow squash sauteed then simmered in store-bought marinara. Spinach is stirred in right before serving.
As far as the taste goes, it was good. Mild flavors, depending on the marinara you use. To me it got just a little bland, but it was nothing that a little more cheese wouldn't fix. Or some chili flakes. The texture might seem too mushy to some, but the majority of people in this house like cooked veggies to be pretty soft.
I give this recipe 2 thumbs up for sure. I will definitely make it again, but I'll add a protein and use less yellow squash.
You can find the entire recipe here, in the Pioneer Woman's Tasty Kitchen.