Potato and Celery Root Gratin

• 2 tablespoons unsalted butter, plus more for the baking dish
• 3 pounds russet potatoes, peeled
• 2 pounds (2 large) celery root, peeled
• 3 cloves garlic, minced
• 2 cups whole milk
• 2 cups heavy cream
• 1 tablespoon kosher salt
• Freshly ground black pepper
• Whole nutmeg or pinch of ground nutmeg
• 1/4 cup freshly grated Parmesan cheese

1. Preheat the oven to 375F.
2. Butter a 9 by 13-inch baking dish.
3. With a mandoline or other vegetable slicer, slice the potatoes and celery roots about 1/16 inch thick.
4. Keep the two vegetables separate.
5. Warm the butter in a 6-quart pot over medium heat.
6. Add the garlic and saute until fragrant, about 1 minute.
7. Add the milk and cream and bring to a simmer.
8. Add the celery roots and cook for about 3 minutes, then add the potatoes, salt, several grinds of black pepper, and a few gratings of nutmeg.
9. Cook, stirring, until the liquid thickens, about 7 minutes.
10. Stir in the cheese.
11. Transfer to the baking dish and spread evenly with a wooden spoon.
12. Bake until the potatoes and celery root are tender when pierced and the top is lightly browned, about 40 minutes.
13. Serve warm, not hot.

unsalted butter, russet potatoes, celery root, garlic, milk, heavy cream, kosher salt, freshly ground black pepper, nutmeg, freshly grated parmesan cheese

Taken from www.epicurious.com/recipes/food/views/potato-and-celery-root-gratin-388245 (may not work)