Sweet Potato and Turnip Gratin

1. 1

   Preheat the oven to 350F.

2. 2

   Butter a 3-quart casserole.

3. 3

   To blanch the turnips, bring a large pot of water to the boil.

4. 4

   Add the sliced turnips and cook 5 minutes.

5. 5

   Remove them and drain thoroughly in a strainer.

6. 6

   Gently combine the turnips and sweet potatoes.

7. 7

   Place a layer of the vegetables in the casserole and dot with half the butter.

8. 8

   Sprinkle generously with tarragon, salt, and pepper, and cover with half of the Parmesan.

9. 9

   Make another layer.

10. 10

    Top with the bread crumbs and pour the cream around the sides.

11. 11

    Dot with the remaining butter and Parmesan.

12. 12

    Bake until the vegetables are soft but not mushy, 1 to 1 1/2 hours.

13. 13

    The gratin can be made ahead several days, or frozen for up to 3 months.

14. 14

    Let defrost in the refrigerator and reheat for 30 to 45 minutes in the oven, or reheat in the microwave.

15. 15

    Omit the sweet potatoes and double the amount of turnips.

* Per serving · 4 servings · Values may vary.