Melt butter in a Dutch oven over medium heat. Sauté onions, carrots and broccoli until onions are translucent (6-8 minutes). Add mushrooms, squash, garlic and water then saute for 2 minutes longer.
Add remaining ingredients, stir well and bring to a simmer. Cook for 8 to 10 minutes or until veggies are tender and flavors are well-blended.
Serve over cooked pasta. Sprinkle Parmesan over the top and serve.