Squeeze spinach to remove excess liquid. Trim 1 inch off end of each lasagna sheet; discard trimmed ends. Spread 2 Tbsp. dressing onto bottom of 9-inch square baking dish sprayed with cooking spray. Top with 1 lasagna sheet, 2 Tbsp. of the remaining dressing, and 1/3 each
of the mushrooms, spinach and tomatoes; sprinkle with 1/3 of the goat cheese. Repeat layers twice, adding half the mozzarella to one of the layers; cover with remaining lasagna sheet. Top with remaining dressing and mozzarella; sprinkle with Parmesan.