Bring 4 quarts water to a boil in a large Dutch oven. Add pasta; cook 5 minutes. Add carrots; cook 2 minutes. Add peas; cook 30 seconds. Drain and rinse with cold water; drain well.
Heat oil in a large nonstick skillet over medium-high heat. Add the green onions and garlic, and sauté for 2 minutes. Add pasta mixture, broth, pattypan squash, and zucchini, and bring to a boil. Cover, reduce heat, and simmer until thoroughly heated. Stir in arugula and remaining ingredients.
I love this simple, light dish. There is nothing in the flavors that particularly wows you, but it is easy to make and really hits the spot when you just want something light and satisfying for dinner.