Sweet Potato Tart

1 1/2 cups flour
1/2 cup brown sugar
1/4 cup butter
1 egg
2 T toasted pecans, chopped
1 (17oz) sweet potatoes in light syrup
1/3 cup plain yogurt
1/2 cup brown sugar
1 T flour
1/2 t ground ginger
1/2 t ground cinnamon
1/4 t ground cloves
1/4 t ground nutmeg
2 egg whites
1/2 cup milk

Heat oven to 400º. For crust, In large bowl mix flour, sugar, butter, egg and pecans. Press mixture onto bottom and along sides of a 9" springform pan. Bake at 400º for 8-10 minutes until lightly brown. Drain sweet potatoes, reserving 1/4 cup syrup. Mash potatoes. Add yogurt, flour, and spices. Stir in egg whites, milk, and reserved syrup. Blend well. Pour sweet potato mixture into crust. Bake at 400º for 10 minutes. Reduce heat to 350º for 50-60 minutes, until toothpick comes out clean. Cool completely before serving.