Earthy rutabagas and aged Gruyere add intrigue to a classic potato gratin. Slicing the root vegetables with a mandoline and cooking the ingredients on the stove top before baking results in an especially luscious dish. This recipe first appeared in our November 2011 issue along with Linda Monastra’s story True Harvest.
- 4 tbsp. unsalted butter
- 2 tbsp. olive oil
- 4 cloves garlic, finely chopped
- 1 medium red onion, thinly sliced
- 1⁄4 cup flour
- 2 cups milk
- 1 cup heavy cream
- 1 lb. russet potatoes, peeled and very thinly sliced
- 1 lb. rutabagas, peeled and very thinly sliced
- 1 tbsp. minced thyme leaves
- 2 cups (about 4 oz.) grated Gruyére cheese
- osher salt and freshly ground black pepper, to taste
- Heat oven to 425°. Heat butter and oil in a 6-qt. saucepan over medium-high heat; add garlic and onion, and cook, stirring often, until soft, about 6 minutes. Stir in flour, and cook until smooth, about 1 minute. Add milk and cream, and stir until smooth. Add potatoes, rutabagas, and 2 tsp. thyme, and bring mixture to a boil; cook, stirring often, until vegetables are slightly tender and broken apart, about 5 minutes. Stir in half the cheese and salt and pepper, and then transfer to a 9″ × 13″ baking dish; top with remaining cheese and bake until golden brown and bubbling, about 25 minutes. Sprinkle with remaining thyme before serving.