Cook pasta according to package instructions. Prepare zucchini sauce while pasta cooks.
Peel and mince garlic.
In a large skillet over medium heat, heat oil. Add zucchini and minced garlic. Cook until mixture softens and zucchini yields some liquid, about 5 minutes.
Drain pasta, reserving ½ cup cooking liquid.
Add 1-2 teaspoons cooking liquid to zucchini mixture. Add drained pasta. Stir, coating pasta evenly with sauce. Add more pasta water as needed.
Transfer pasta to a large bowl for serving. Sprinkle with grated Parmesan. Season with salt and pepper. Toss to combine.
Notes
Use yellow squash in place of the zucchini. Or, use a mix of both.
For faster cooking, grate zucchini in advance. Refrigerate until you are ready to cook.
Make a simple pasta salad. Mix raw grated zucchini with cooked and cooled pasta, canola oil, mint, basil, or other herbs.
Add more veggies in step 4 if you like. Try diced carrots or tomatoes, peas, or corn.