Combine the garlic, parsnips, potato, and enough stock to cover the vegetables in a large saucepan. Add a generous pinch of salt and bring it to a boil over high heat. Reduce the heat and simmer for about 20 minutes or until the vegetables are quite tender.

Scoop out about a cup of the hot stock and set aside. Drain the vegetables and return them to the pot. Mash with the crème fraîche and butter, but leave the mixture slightly chunky. You can use a food mill or a ricer if you prefer a smooth puree. If the mash seems dry, stir in some of the leftover stock. Keep the rest of the stock for serving at dinner.

Stir in the nutmeg and season with salt and pepper to taste. Keep warm and covered, reheating over medium-low heat just before serving and adding a little more stock if necessary.