Mix the ricotta, 3 cups mozzarella, parmesan, egg, 2 tablespoons minced garlic, and Italian Seasoning in a large bowl. Set aside.
In a very large pan or dutch oven, saute the remaining garlic in the olive oil. Add the mushrooms, zucchini, yellow squash, and carrot, and cook until the squash is translucent and slightly browned. Add the spinach to the pan, and cook briefly until limp.
Pour in the pasta sauce and water, and bring to a boil. Add the frozen broccoli florets, and cook until thawed.
In a 9x13 pan, put one or two ladles full of the sauce mixture (with as few of the vegetables as possible). Then start building your lasagna as follows: uncooked lasagna noodles, one third of the cheese mixture, one third of the sauce, repeat. When finished, sprinkle the reserved mozzarella on top.
Bake, covered with aluminum foil, for 45 minutes. Uncover and continue baking for 10-15 minutes longer, until the cheese is brown and bubbly.
Delicious with a crisp salad and italian bread on the side!