Drizzle with oil; sprinkle with salt and 1/8 teaspoon pepper.
Bake at 400° for 15-20 minutes or until tender, stirring occasionally.
Meanwhile, in a small saucepan, heat broth and keep warm. In a large nonstick skillet, saute onion in butter until tender.
Add orzo and garlic; cook and stir for 2-3 minutes. Carefully stir in 1 cup warm broth. Cook and stir until all of the liquid is absorbed.
Add remaining broth, 1/2 cup at a time, stirring constantly. Allow the liquid to absorb between additions. Cook until risotto is creamy and orzo is almost tender. (Cooking time is about 20 minutes.)
Add the herbs, cooked squash and remaining pepper; heat through.
Garnish with cheese if desired; serve immediately.