This vegetarian lasagna, which is bubbling with gooey cheese, is a delicious way to sneak lots of vegetable servings into dinner.
For the sauce:
Heat olive oil in a large sauté pan over medium high heat. Add zucchini, squash, onion and red peppers. Season with salt and sauté vegetables until softened, about 5 minutes. Add garlic and cook an additional minute. Pour in marinara sauce and chopped basil. Add a pinch of red pepper flakes. Cook sauce for 20-30 minutes, stirring occasionally, until slightly thickened.
For the lasagna:
While sauce is cooking, mix together ricotta cheese and egg until combined. Season with salt and pepper.
In a 9x13-inch baking dish, assemble the lasagna: Spoon vegetable sauce on bottom, cover with noodles in a single layer, spread a layer of the ricotta mixture and sprinkle some Parmesan. Repeat until the lasagna is fully built, finishing by covering the top with the shredded mozzarella.
Cover lasagna with aluminum foil. Bake in a 400°F oven, covered, for 40 minutes, then remove foil and cook for an additional 10 minutes, until the cheese turns golden brown.
Once cooked, let lasagna sit for 8-10 minutes before cutting and serving.