In a large bowl, mix together the flour, sugar, and kosher salt. Using a box grater, grate the cold butter atop the flour mixture. Transfer to the freezer to chill for 10 minutes. Working quickly, and using your hands, break the butter bits into the flour until they’re evenly distributed and resemble the size of teeny, small peas.

Add 50% of the recommended water and mix. The mixture will be shaggy at this point. From here, add 1 tablespoon of water at a time until the dough comes together. Flour your counter and dump the dough onto it. Gather the mixture into a rough square and press down gently. Fold it in thirds like a letter and give it a quick press and then repeat again, this will create some “layers”. Divide the dough, forming two rectangles (mine were roughly 3 inches by 5 inches by 1 inch). Wrap the bricks in plastic wrap and transfer them to the refrigerator to chill for at least 2 hours, ideally overnight.

Peel, core, then dice your apples into ¼-inch cubes. In a saucepan, toss them together with lemon juice, lemon zest, brown sugar, granulated sugar, kosher salt, flour, cinnamon, and nutmeg, and cook over medium-low heat for 10 minutes, stirring often. Let cool for 30 minutes or until at room temperature.

Remove the first brick of dough from the fridge. Lightly flour your work surface and roll the dough out into a 9-inch by 12-inch rectangle. Trim any excess using a bench scraper or something similar. Cut into 3-inch by 4-inch rectangles. You should have 9 pieces in total. Place them on a parchment-lined baking sheet, spacing evenly. Repeat this with the other brick, placing the rectangles on another sheet of parchment, right over the existing parchment on the baking sheet.

Stick the sheet in the freezer for about 10 minutes just to firm the dough up a bit. Take the top sheet of parchment off of the sheet. Place 3 tablespoons of apple filling in the middle of each rectangle, leaving a 1/2-inch border. Quickly roll each top rectangle out a little to accommodate the heaping mound of apples. Put each rectangle on top of the apple mound rectangles and press the edges together. Use the tines of a fork (dipped in flour if sticking) to crimp the pieces together and create a nice decoration.

Transfer them to the freezer to chill for about 10 minutes. Meanwhile, preheat the oven to 425 degrees F.

When the hand pies are done chilling and the oven is preheated, brush the tops with the remaining egg wash. Transfer to the oven (I did this in batches) for about 15 to 20 minutes, until the tops are golden brown. Let cool on the sheet to room temperature.

In a small bowl, whisk together the icing sugar, heavy cream, butter, vanilla extract, and salt. Spoon into a plastic zip bag.

When the pies are at room temperature, snip off the bottom edge of the plastic bag (a small snip) to create a piping tip. Pipe on icing and enjoy.