Divide the dough in half. Roll each half into a circle and fit into a 9-inch pie pan, finishing the edge of each crust as desired. Refrigerate until ready to use.
Rinse the sweet potatoes and place in a large pot. Add enough water to cover them. Over medium-high heat, bring the water to a boil. Cook until the sweet potatoes are completely tender, about 1 1/2 hours. Remove the potatoes from the water.
Put the butter into the large bowl of a standing electric mixer. Carefully peel each potato (because they are hot), also removing any brown flesh. Add the hot potatoes to the butter and mash them until smooth.
Preheat the oven to 250 degrees.
Beat the sweet-potato mixture with the white and brown sugars until smooth. Add the sweetened condensed milk, nutmeg and cinnamon to taste and the lemon juice. Mix on low until thoroughly combined, adding the eggs until they are just combined.
Divide the pecans between the two prepared crusts, reserving about 1/3 cup of the best-looking halves to garnish the pies. Pour the sweet potato filling over the nuts, dividing the batter between the two pies. Top each pie with the pecan halves, arranging them as desired.
Bake the pies for 1 hour. Raise the heat to 350 degrees and bake until the pies are firm, the crust has begun to brown and the pies have puffed a little, 25 to 30 minutes.
Servings: 20 Yield: Makes two 9-inch pies or 20 servings
Source: "Christine Taylor's Sweet Potato and Pecan Pie" http://www.washingtonpost.com/recipes/christine-taylors-sweet-potato-and-pecan-pie/7639/?utm_term=.219f377abb63