Joyce Sangirardi, who works in the Martha Stewart Living test kitchen, borrowed this recipe from her sister, Cecilia Stella. We can't promise your satisfied guests won't beg to borrow the recipe from you, too.
On a lightly floured surface, roll out dough to a 13-inch round about 1/8 inch thick. Brush off excess flour. Wrap the dough around the rolling pin, and lift it over a 9-inch pie plate. Line the pan with the dough, pressing it into the sides. Trim dough, leaving about 1/4 inch overhang all around; fold dough under to form a rim. Crimp edge with a fork. Cover with plastic wrap, and chill in refrigerator at least 30 minutes or up to 1 day.
Preheat oven to 375 degrees, with rack in center. Prick bottom of dough all over with a fork. Line with parchment paper, pressing into corners, and fill with pie weights or dried beans. Bake until edges begin to turn brown, 15 minutes. Remove pie weights, and bake 8 minutes more. Transfer to a wire rack to cool.
Combine sweet potatoes and butter in the bowl of an electric mixer fitted with the paddle attachment. Beat on medium speed until smooth. Add 1/2 cup brown sugar, maple syrup, bourbon (if using), vanilla, cinnamon, salt, and nutmeg. Mix until well combined. Add half-and-half, 1 egg, and the egg yolk; mix until smooth.
Sprinkle the remaining 3 tablespoons brown sugar and the chopped pecans evenly over bottom of prepared crust. Pour in filling. In a small bowl, combine remaining egg and cream; brush this egg wash evenly over edge of crust. Return to oven; bake until set, 30 to 40 minutes. Transfer to a wire rack to cool. Serve with bourbon whipped cream.