Sweet Potato Tart

1-1/2 cups all-purpose flour
1/2 cup packed brown sugar
1/4 cup cold butter, cubed
2 tablespoons chopped pecans, toasted
1 egg
FILLING:
1 can (15-3/4 ounces) sweet potatoes
1/2 cup packed brown sugar
1/2 cup fat-free milk
2 egg whites
1/3 cup reduced-fat plain yogurt
1 tablespoon all-purpose flour
1/2 teaspoon ground cinnamon
1/4 teaspoon ground ginger
1/4 teaspoon ground nutmeg
1/8 teaspoon ground cloves
Whipped topping, optional

In a food processor, combine the flour, brown sugar, butter and pecans. Cover and pulse until blended. Add egg, pulsing until mixture forms a soft dough. Press onto the bottom and up the sides of a 9- in. fluted tart pan with removable bottom. Place pan on a baking sheet. Bake at 400° for 8-10 minutes or until lightly browned. Cool on a wire rack. Reduce heat to 350°.
Drain sweet potatoes, reserving 1/4 cup liquid. Place potatoes in a food processor; cover and process until pureed. Add the brown sugar, milk, egg whites, yogurt, flour, cinnamon, ginger, nutmeg, cloves and reserved liquid;
cover and process until blended. Pour into crust. Bake for 30-35 minutes
or until a knife inserted near the center comes out clean. Cool on a wire rack. Store in the refrigerator. Garnish with whipped topping if desired. Yield: 12 servings.