Bring a large saucepan of water to a boil. Combine broth and garlic cloves in a small saucepan; bring to a boil over high heat. Cover, reduce heat to a simmer and cook until the garlic cloves are soft, about 15 minutes.
After the garlic has simmered about 10 minutes, cook fettuccine in the boiling water, stirring often, for 8 minutes. Drop in zucchini and cook until the fettuccine is just tender, about 1 minute more.
Meanwhile, transfer the garlic and broth to a blender. Process until the mixture is smooth, about 1 minute. (Use caution when blending hot liquids; see Tip, page 244.) Return the mixture to the pot and bring to a simmer over medium-high heat. Add cornstarch mixture; whisk it until slightly thickened, about 15 seconds. Remove from the heat and whisk in sour cream, nutmeg and pepper. Return the pot to very low heat to keep the sauce warm. (Do not boil.)
Drain the pasta and place in a large bowl. Add the sauce and 1/2 cup Parmesan; toss to coat well. Sprinkle with parsley and serve immediately, passing the remaining 1/4 cup Parmesan separately.
Tips for Two--Broth Storage: Leftover canned broth keeps up to 5 days in the refrigerator or up to 3 months in your freezer. Leftover broth in aseptic packages keep for up to 1 week in the refrigerator. Uses: Add to soups, sauces, stews; use for cooking rice and grains; add a little when reheating leftovers to prevent them from drying out.
Recipe courtesy EatingWell.com