For the crust, combine the rice flour, tapioca starch, sugar and salt. Cut the cream cheese into large pieces and the butter into pieces about half that size (so that they work into the dough evenly) and cut in until the dough is a rough, crumbly texture. In a small bowl, whisk the whites until frothy and then add to the dough, mixing until it comes together. Shape the dough into 2 discs, wrap and chill until firm, about an hour.
For the filling, toss the pears and cranberries with the sugar, tapioca starch, zest, vanilla and allspice.
Preheat the oven to 375 F. Pull the first disc of pastry from the fridge, unwrap it, sprinkle lightly with rice flour and place it between 2 sheets of parchment paper. Roll the dough into a circle bout 12 inches across. Remove the top layer of parchment paper and transfer the pastry to a 9-inch pie plate and peel away the remaining layer of parchment. Fill the pie with the fruit filling.
Roll the second disc of dough in the same manner and place it on top of the fruit filling. Trim and pinch the edges of the dough and use scissors or a paring knife the cut holes in the top to allow steam to escape. Brush the top of the pie with the egg wash and place the pie on a parchment or foil-lined baking tray. Bake the pie for about 50 minutes, until the crust is a rich brown and the filling is bubbling. Cool the pie completely to room temperature before slicing, or chill and serve cold.