Pierce sweet potatoes several times with a fork, and place on an aluminum foil-lined baking sheet.
Bake at 400° for 1 hour or until done; cool slightly. Peel and cut crosswise into 1/4-inch-thick slices.
Place apple slices in an even layer in a lightly greased 13- x- 9-inch baking dish; top with sweet potato slices.
Stir together 1 1/2 cups orange juice and next 6 ingredients. Pour over sweet potato mixture. Dot with 6 tablespoons butter.
Sprinkle 1/2 cup chopped pecans on a cutting board. Unfold 1 piecrust, and place on pecans; gently roll piecrust dough into pecans. Cut with a leaf-shaped cookie cutter; place leaves over sweet potato mixture. Repeat procedure with remaining 1/2 cup chopped pecans and piecrust.
Microwave remaining 2 tablespoons butter in a 1-cup glass measuring cup at HIGH 20 to 30 seconds or until melted. Brush butter over crust, and sprinkle with 2 teaspoons granulated sugar.
Bake at 400° for 45 minutes or until golden. Serve warm with Bourbon Whipped Cream, if desired.