In a large non-stick skillet over high heat, brown the zucchini in 1 tbsp (15 ml) of the oil. Season with salt and pepper. Set aside on a plate.
In the same skillet over medium heat, soften the onion and garlic in the remaining oil (2 tbsp/30 ml). Add the tomatoes. Stir and bring to a boil. Let simmer for about 15 minutes or until the sauce begins to thicken.
Meanwhile, in a large pot of salted boiling water, cook the spaghetti al dente. Set aside ½ cup (125 ml) of the cooking water for the sauce. Drain the pasta. Set aside.
Add the zucchini and olives to the sauce. Continue cooking for 2 minutes. Season with salt and pepper. Add the pasta to the sauce, and toss to coat. Add the reserved cooking water, if needed. Adjust the seasoning. Top with the basil and Parmesan.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.