This vegetable side dish, perfect for a summer supper, is delicious served warm or at room temperature.
Early in the day prepare sauce. Drain tomatoes and place in a medium bowl with olive oil, garlic, basil, parsley, salt, and oregano. Cover and let stand at room temperature.
Prick the skin of spaghetti squash, and bake on a cookie sheet at 350 degrees F for 1 to 1-½ hours or until tender when pierced with a fork. Let cool and cut in half lengthwise; scoop out any seeds and loose, stringy membrane. With a fork, scrape spaghetti strands of squash from shell into a large bowl. Cover and set aside.
Steam broccoli, zucchini, and summer squash until each is fork tender; rinse in cold water to retard further cooking and keep fresh color. Heat olive oil in large skillet and saute scallions until soft. Add steamed vegetables and heat thoroughly. Toss spaghetti squash with hot vegetables and tomato sauce. Sprinkle with Parmesan cheese and season with pepper.