Add flour, sugar, salt, and butter to food processor bowl. Pulse about 12 times until dry crumbs form.
Add 4 tbsp water. Pulse until you get doughy crumbs. If you feel like you’ve pulsed the food processor a ton (more than 15-ish times) and your consistency still isn’t right, test it by pinching it together. If it’s still crumbly, add 1 tbsp water and pulse again. Pinch, and repeat again as many times as needed.
Transfer the dough to a floured surface and shape into a rectangle.
Wrap tightly with plastic wrap and chill in the fridge for at least 30 minutes.
Toss the diced apples in a bowl with the other ingredients, except for the butter.
Preheat a large saute pan over medium heat.
Melt the butter. Add the apple mixture. Cook until the apples are soft, stirring often so the sugars and flour don’t burn.
Transfer filling to a bowl and set aside. Chill in the refrigerator if you’ll be working with your pie dough soon (you want it cooled to at least room temperature by the time you start assembling the pies).
Preheat oven to 350°.
Roll out crust dough onto a floured surface. Roll until it’s thin, and cut into even strips that are slightly wider than 3 inches. (Confession – I actually used the pasta roller attachment for my KitchenAid stand mixer to roll it out the rest of the way after I rolled it fairly thin. I rolled it to setting #2.)
Scoop filling in even intervals down one dough strip. Top with anther dough strip. Press dough down to seal all around the filling.
Cut out pies with ravioli stamp, pastry wheel, or knife. If using a knife, crimp edges with a fork.
Place pies on a baking sheet lined with a silicone baking mat or parchment paper. Brush each one with egg and sprinkle with sugar. Use a fork to poke holes in the top to vent steam.