Noodleless Lasagna

This is one of my favorites. It's great for entertaining large groups of people and it isn't as heavy as normal lasagna. It's perfect for this time of year when zucchini and summer squash are still in season. It's gluten-free and delicious.

Noodleless Lasagna
4-5 large zucchini or summer squash or both
1 large jar of pasta sauce of your choice, last time I used butternut squash pasta sauce and it was amazing (remember to check the ingredients to make sure you aren't consuming unnatural preservatives)
1 medium onion
3-4 cloves garlic, minced
1 1/2 c. pesto (homemade or store bought, if pure)
4 c. ricotta cheese (2 16-oz. containers)
1 8 oz. ball of buffalo mozzarella

The easiest way to do this is to use a mandoline slicer. They are very inexpensive and you can get them at any store that has kitchen supplies. If you're using the mandoline, slice the zucchini and summer squash lengthwise to get long noodle-like slices. If you don't have access to one, thinly and evenly slice your zucchini and summer squash to resemble lasagna noodles.
Using the mandoline or a knife slice the onion and then separate into single rings. Preheat the oven to 350 degrees. In a deep 9" by 13" pan put a thin layer of the pasta sauce on the bottom. Then layer some onion and then fully cover with one layer of the squash.
Layer on one cup of the ricotta followed by a thin layer of pesto. Repeat layers of onion, squash, ricotta, pasta sauce. Keep repeating layers rotating the use of pesto and pasta sauce until ingredients are gone or you reach the top of the pan. End with a layer of squash, a thin layer of pasta sauce and chopped up pieces of mozzarella. Sprinkle the top with the minced garlic and bake for about an hour, until the squash is soft. Let set for about 20 mins and serve. Season with sea salt to taste and enjoy! Cooking the squash releases water so it's a little soupy, but still delicious. It'd be great served with garlic bread (gluten-free if you choose).
***Variations:
No pesto? Layer with basil leaves
Using a sauce that isn't tomato based? Layer with tomatoes
Layer with any vegetables you want: potatoes, egg plant, mushrooms, spinach...