Whisk together the flours and salt in a medium bowl to combine.
Beat the butter and powdered sugar in the bowl of an electric mixer on medium speed for 2 to 3 minutes, until well combined. Add the egg and egg yolk, one at a time, blending well after each addition. With the mixer on low speed, add the flour mixture in two additions, blending until just incorporated. Transfer the dough to a lightly floured work surface and divide in half. Shape each piece into a flat disk and wrap in plastic wrap. Chill one piece of dough in the refrigerator for at least 1 hour, or overnight. Place the other half in the freezer for another use.
Toss together the apples, pears, cranberries, orange zest, lemon zest, orange juice, lemon juice, sugar, cinnamon, and nutmeg in a large bowl to combine.
Preheat the oven to 400°F and line a large rimmed baking sheet with parchment paper. Transfer the chilled dough to a lightly floured work surface and roll into a 12-inch circle, about ¼-inch thick. Transfer the dough to the prepared baking sheet. Pour the fruit onto the center of the dough and gently fold the edges of the dough over the fruit, pressing gently to seal.
Brush the edges of the dough lightly with the egg wash. Bake for 40 to 45 minutes, until the crust is golden brown and the fruit is tender. Remove from the oven and let cool slightly before serving.