Whipped Sweet Potatoes with Pecan Streusel Topping

5 pounds sweet potatoes, peeled and cut in 1/2-inch pieces

1/2 cup light brown sugar

2 teaspoons orange zest

1 tablespoon orange juice

1 teaspoon cinnamon

1/2 teaspoon ground allspice

1/2 teaspoon ground nutmeg

1 teaspoon salt

3 large egg whites


1/2  cup packed light brown sugar

1/4 cup all-purpose flour
1/4 teaspoon ground cinnamon

3 tablespoons cold unsalted butter, cut in bits

2/3  cup chopped pecans

  1. Fill a large pot 3/4 of the way with water and add the potatoes. Bring to a boil, reduce heat and simmer for 25 minutes, or until potatoes are very tender. Drain and puree in a food processor or blender until smooth. (You may have to work in batches). Combine the potatoes with the brown sugar, orange juice and zest, cinnamon, allspice, nutmeg and salt.
  2. Make the streusel topping: combine the brown sugar, flour, and cinnamon in a bowl and cut in the butter. Stir in the pecans and keep refrigerated until you’re ready to bake the casserole. The dish may be made up until this point, keeping the potatoes and topping separate, up to 2 days in advance.
  3. Preheat the oven to 400F. Coat a 9 x 13 baking dish with cooking spray.
  4. Just before baking, whip the egg whites until they form soft peaks. Stir 1/4 of the egg whites into the potatoes, then gently fold the remaining egg in. Transfer to the baking dish and top with the streusel. Bake 30 minutes, or until the top is lightly browned and a thermometer inserted in the center of the casserole registers 160F. (If your oven is hot and the topping is browning too quickly, coat a piece of foil with cooking spray and lie it loosely across the top of the dish.)