Heat a large wok or extra large pan over medium heat. Melt butter and add sliced apples. Mix to ensure that all apples are coated thoroughly in butter. Add sugars, salt, and all spices and mix well. Cook apples for about 8-10 minutes, until slightly browned and softened. Remove from heat and place in a shallow heat safe bowl or plate to cool completely. (once slightly cooled, I put chill it in the refrigerator). Add cornstarch and mix very well.
At least 1 hour before you need to bake the pie, prepare the dough. In a large bowl, combine flour, sugar, and salt. Add cold cubed butter to the flour mixture and toss around with hands to coat the cubes of butter in flour. With the thumbs and fingers, flatten out all the pieces of butter while rubbing the butter into the flour as well. You’ll end up with some large pieces or flattened butter and some smaller varying pea sized pieces. Add sprinkles, toss around, and rub them in just a bit. Create a well in the middle of the flour mixture and add 6 tablespoons of water. With a large spoon or spatula, fold the flour into the water slightly. Add the rest of the water and fold again. Bring the dough together with your dominant hand by scooping the mixture from the bottom of the bowl and bringing it up and over and knead the dough a few times very lightly. If the dough feels too dry, sprinkle in a tiny bit of water.Dump dough out onto a clean surface and bring together into a tight rectangle. Divide dough in half and tightly wrap in plastic wrap. Chill dough in fridge for at least 1 hour or preferably, overnight.
If pie dough chilled in the fridge for over 3 hours, let it sit on counter for about 10 minutes before rolling. On a heavily floured surface and with a floured rolling pin, flatten and roll out pie dough, lifting and turning it every couple rolls to make sure it doesn’t stick. Add more flour to the surface if needed. Roll dough out to 1/8 inch thickness in a rectangle shape. Roll up one side onto your rolling pin to help you place it onto the baking sheet. Lightly press the dough into the baking sheet without stretching the dough. Trim the edges so that you only have about 1/2 inch overhang around the edges. Fill with completely cooled apple filling. Set aside in refrigerator to chill.
Preheat oven to 425 degrees F with the oven rack in the lower third of the oven.Roll out second pie dough in the same way. For a lattice design, cut into even strips and weave a lattice design over the top of the pie. Alternatively, you can just drape the entire top crust over the filling and cut vent holes before baking.Trim the edges again and crimp tightly all around the border.
Beat the egg and milk together in a small bowl. Brush egg wash all over the top crust and sprinkle sugar on top. Bake for 15 minutes, then lower the temperature to 375 degrees F (without opening oven door!) and continue baking for another 40-45 minutes, until crust is a deep golden brown.
When pie is completely cool, mix confectioner’s sugar and milk in a medium bowl. Add more sugar if glaze is too thin, or more milk if glaze is too thick. Drizzle over the pie, add your favorite sprinkles