Potato & Leek Gratin

cooking spray
1 pound leeks, cleaned well, tough outer layer removed, trimmed to about an inch of green above the white bulb, cut in 1-inch lengths
2 tablespoons unsalted butter
3 ounces good quality white bread
1-½ ounces Reggiano Parmigiano, cut in ½-inch pieces
6 ounces Gruyère cheese (not processed gruyère)
2-¼ pounds russet or gold potatoes, peeled, cut flat at ends
1 can (12-ounce) evaporated skimmed milk, not reconstituted
1-¼ cups lowfat milk
½ cup heavy cream
¾ teaspoon freshly grated nutmeg
¾ teaspoon freshly ground black pepper
1 teaspoon kosher salt

Calories 248 (44% from fat) - carb. 24g - pro. 11g - fat 12g - sat. fat 7g - chol. 39mg - sod. 396 mg

Preheat the oven to 375º F. Spray a shallow 2-½-quart ovenproof casserole dish with cooking spray. Cut a sheet of aluminum foil large enough to cover the casserole, spray one side of the foil with cooking spray and set aside. Insert the metal blade. Place leeks in work bowl and pulse to chop, about 10 pulses. In a medium skillet, melt 1 tablespoon of the butter. Add the leeks, and cook over low heat for 20 to 25 minutes until they are light caramel in color. Remove from the heat and allow to cool. Wipe out work bowl to dry. Add the bread to the work bowl and pulse to achieve coarse crumbs, about 20 to 25 pulses. With the machine running, drop the butter down the small feed tube and process until the crumbs are medium and the butter is evenly distributed, about 30 seconds. Remove and reserve. With the machine running, drop the Parmesan down the small feed tube and process to chop finely, 10 to 15 seconds; leave in work bowl. Insert the shredding disc; shred the Gruyère using medium pressure. Add one half cup of the cheeses to the breadcrumb mixture, reserve. Remove and reserve the remaining cheeses. Insert the slicing disc. Use medium pressure to slice the potatoes. Neatly layer ⅓ of the potato slices in the bottom of the casserole. Top with ½ the grated cheeses and ½ of the cooled caramelized leeks. Repeat, ending with a layer of the potatoes. In a large saucepan, combine the milk, cream, nutmeg, pepper and salt. Stirring, bring this mixture to a boil. Carefully pour over the layered potatoes, leeks and cheeses. Top evenly with the buttered crumb and cheese mixture. Loosely cover with the foil and place in the preheated oven for 1-½ hours. Test the potatoes for doneness. Depending on the type of potato, it may take up to 2 hours until tender. When the potatoes are tender, remove the foil and bake for 15 to 20 minutes longer, until the topping is light golden and crispy. Allow the gratin to rest for 15 to 20 minutes before serving.