Creamy Ham and Leek Gratin

• MAKE-AHEAD

Ingredients

1. 4 cups water
2. 6 medium leeks, white and tender green, split lengthwise
3. 1/2 cup dry white wine
4. 1 bay leaf
5. Salt
6. 1 cup heavy cream
7. 1 large shallot, thinly sliced
8. 1 tablespoon fresh lemon juice
9. Freshly ground pepper
10. 6 ounces baked smoked ham, cut into 2-by- 1/2 -inch matchsticks
11. 2/3 cup unsalted pistachios (about 3 ounces), coarsely chopped
12. 2 tablespoons unsalted butter, melted

1. In a large skillet, bring the water to a boil. Add the leeks, wine, bay leaf and a large pinch of salt and simmer over moderate heat until the leeks are tender, about 25 minutes. Using a slotted spoon, transfer the leeks to a plate, keeping them intact. Add the cream and shallot to the cooking liquid and simmer over moderate heat until reduced to 1 1/4 cups, about 6 minutes. Add the lemon juice and season with salt and pepper.
2. Preheat the oven to 500°. Arrange the leeks, cut side up, and the ham in a large gratin dish. Pour the cream sauce evenly over the leeks and ham. In a small bowl, combine the pistachios and melted butter and scatter over the leeks. Bake in the upper third of the oven for about 8 minutes, or until golden brown on top. Serve piping hot.