Cover; simmer on medium heat for 15 min, stirring occasionally. It will thicken near the end of the cook time; stir more frequently at that time to prevent sticking. Season with salt and pepper to taste.
Meanwhile, using a vegetable spiralizer, form zucchini into thin noodles. You should have about 6 cups. Place in a Round or Multipurpose Steamer. Cover; microwave on high at 2 min intervals until tender-crisp, about 4 min, stirring gently after each interval to ensure even cooking. Season with salt and pepper to taste.
To serve, divide zoodles between six bowls. Spoon sauce on top, then add cheese and additional toppings, if desired.
Per serving: Calories 200, Fat 5 g (Saturated 1 g, Trans 0 g), Cholesterol 5 mg, Sodium 590 mg, Carbohydrate 23 g (Fiber 6 g, Sugars 5 g), Protein 19 g.
No spiralizer? Use the Y Peeler to make thin ribbons or the 4-in-1 Mandoline fitted with the julienne plate. Or look for pre-spiralized zucchini in the fresh produce section of most grocery stores.