Preheat oven to 425 degrees
Spray a roasting pan or cookie sheet with a little oil olive spray
Dice the summer squash, tomatoes, onions into 1 inch pieces (try to have them uniform in size)
Place on pan, drizzle with olive oil
Sprinkle salt and pepper over all the vegetables
Roast for 25 to 30 minutes
While vegetables are roasting bring water to a boil and cook pasta according to the package directions
Drain the pasta and return to pot
Over low heat, add the butter to the pasta and stir
Stir the roasted vegetables into the pasta
Add more salt and pepper if needed
Mix in the Parmesan cheese
Serve