With vegetable peeler remove the thick skin from rutabaga and cut into 1½-inch square pieces. Place the rutabagas and garlic in a large pot and add enough lightly salted water to cover. Cover tightly and bring to a boil over high heat. Uncover and reduce heat to medium-low. Boil gently for 20 minutes.

Add the onion and continue cooking until the rutabagas are tender when pierced with a knife, 15 to 20 minutes more. Drain well and return to the warm cooking pot.

Add the Parmesan cheese, butter, salt and pepper. Using a large masher or electric hand mixer, mash the rutabagas gradually adding enough milk to reach desired consistency. Transfer to a warm serving dish. The rutabagas can be kept warm in a 170˚F oven covered with aluminum foil for up to 20 to 30 minutes. Serve hot.

Note: For best flavor use Parmigiano-Reggiano. The cookbook called for turnips but we tought rutabagas were a better choice since they are a little less bitter.