We love the layered look of this ever-so-sweet streusel-topped treat.
Preheat oven to 375°. Fit piecrust into a 9-inch deep-dish pie plate; fold edges under, and crimp. Bring potatoes, next 2 ingredients, and 1 cup water to a boil in a Dutch oven. Cover, reduce heat to medium, and simmer 6 minutes or until potatoes are just tender.
Transfer potatoes to a large colander, reserving cooking liquid. Rinse potatoes with cold water. Transfer cooking liquid and orange peel strips to a small saucepan, and bring to a boil over medium-high heat. Reduce heat to medium, and simmer, stirring occasionally, 10 to 12 minutes or until reduced to 1/4 cup. Reserve 2 Tbsp. potato-orange liquid; discard remaining liquid.
Transfer potatoes to a bowl; toss with brown sugar, next 4 ingredients, and reserved 2 Tbsp. potato-orange liquid. Spoon into crust; sprinkle with streusel.
Bake at 375° for 1 hour and 5 minutes to 1 hour and 15 minutes, shielding with aluminum foil after 30 minutes to prevent excessive browning. Cool completely.