For the dough, place the softened butter, sugar and salt in the bowl of an electric mixer; beat on high speed until the mixture is creamy. Add the egg and beat 30 seconds. Add the milk and beat 2 minutes. Add the flour and beat on medium speed 5 seconds, then on high speed Just until blended, about 5 seconds more (over- mixing will produce a tough dough). Remove the dough from the bowl and shape in to one 5-inch patty; lightly dust with flour and wrap In plastic wrap; refrigerate at least 1 hour, preferably overnight. (The dough will last up to one week refrigerated.) On a lightly floured surface roll out dough to 1/8 to 1/4 inch thickness. Very lightly flour the top of the dough and fold it into quarters. Carefully place dough in a greased and floured 8-inch round cake pan so that the corner of the folded dough is centered in the pan. Unfold the dough and arrange it to fit the sides and bottom of pan; press firmly in place. Trim edges. Refrigerate 15 minutes.
For the sweet potato filling, combine all the ingredients in a mixing bowl. Beat on medium speed of electric mixer until the batter is smooth, about 2 to 3 minutes. Do not over-beat. For the pecan pie syrup, combine all the ingredients except the pecans In a mixing bowl. Mix thoroughly on low speed of electric mixer until the syrup is opaque, about 1 minute; stir in pecans and set aside.
To assemble, spoon the sweet potato filing evenly into the dough-lined cake pan. Pour the pecan syrup on top. Bake in a 325F oven until a knife inserted in the center comes out clean, about 1-3/4 hours. (The pecans will rise to the top during baking) Cool and serve. Store pie at room temperature for the first 24 hours, then refrigerate.
Cajun Country -- New Iberia, Louisiana