Arrange zucchini, yellow squash, carrot, and broccoli flowerets in a vegetable steamer over boiling water.

Cover and steam for 4 to 5 minutes, or until vegetables are crisp-tender.

Drain the steamed vegetables and set aside.

Preheat oven to 375°F (190°C).

In a bowl, combine the steamed vegetables, mushrooms, onion, tomato sauce, garlic powder, Italian seasoning, basil, pepper, and salt.

In a separate bowl, mix the cottage cheese and thawed egg substitute.

Spread a thin layer of tomato sauce mixture on the bottom of a baking dish.

Layer with lasagna noodles, cottage cheese mixture, and vegetable mixture.

Repeat layers until all ingredients are used, finishing with a layer of tomato sauce and mozzarella cheese.

Cover with foil and bake for 30 minutes.

Remove foil and bake for another 10 minutes, or until cheese is melted and bubbly.

Let stand for 10 minutes before slicing and serving.