Dissolve the powdered milk in the 1 cup of water and set aside.
Place pie crust in 9 inch pan and spread the cashews evenly over the bottom of the crust.
In a food processor grate the potato until finely chopped adding enough of the reconstituted milk to make it smooth but not very wet; use no less than 2 Tablespoons but no more than 1/4 cup.
Grate the the lemon rind and add to the potato mixture, if you peel long strips of zest off the lemon without getting any white on it, you can use the food processor to grate the zest too instead of doing it by hand.
Transfer the potato, lemon mixture to a large mixer bowl;.
with an electric mixer, beat in the eggs, sugar, syrup, vanilla and salt, beating until smooth.
Pour the mixture over the cashews in the pie pan and bake in a preheated 375ºF oven for 40 to 50 minutes or until filling is set.
Check pie crust half way through cooking time, if crust is browning to quickly cover the edges of the crust will foil to stop it from getting to brown before the pie is set.
Cool thoroughly before cutting, serve plain or with whipped cream or vanilla ice cream.