Essential Parsnip Gratin Recipe

Preheat oven to 375 degrees F (190 degrees C). Butter a 2-quart baking dish liberally.

Peel parsnips reserving peelings for broth. Slice into 1/8-inch rounds. Arrange 1/3 of the parsnip slices in a single overlapping layer in the prepared baking dish. Sprinkle 1/3 of the Parmigiano cheese over the top. Repeat with remaining parsnips and Parmigiano cheese.

Heat 1 tablespoon butter in a large skillet over medium heat. Add celery 1/2 of the leeks 1 clove garlic and ginger pieces. Cook until softened about 5 minutes. Add parsnip peelings; season with salt pepper and nutmeg. Add 2 tablespoons water; cook and stir until water is completely absorbed and mixture turns pale brown about 5 minutes more. Continue to cook and stir adding water as needed until well-browned 8 to 10 minutes more.

Pour remaining water over celery mixture; add bay leaves 1 sprig rosemary and Parmigiano rind to skillet. Increase heat to high; bring liquid to a boil. Lower heat cover and simmer until reduced to about 1 cup broth 20 to 30 minutes. Season with salt pepper and nutmeg. Strain broth through a fine sieve pressing solids to extract as much liquid as possible.

Heat remaining butter in a saucepan over medium heat; add remaining leeks remaining garlic and several rosemary leaves. Cook until softened about 5 minutes. Add reserved broth; cook and stir until most liquid has evaporated and mixture is pale brown 10 to 12 minutes. Stir in cream salt pepper and nutmeg to taste; cook and stir until hot about 3 minutes. Pour into prepared baking dish to 3/4 of the way up parsnip layers.

Bake in preheated oven until parsnips are soft cream mixture is thickened and bubbly and top is golden brown 45 to 60 minutes. Cool until gratin is set about 10 minutes. Garnish with more nutmeg and rosemary leaves.