PREHEAT OVEN AND PREP: Preheat the oven to 375 degrees F. Line a baking sheet with parchment paper and set aside.
COOK APPLES: Add 2 medium Granny Smith apples, peeled and finely chopped, 1/4 cup granulated sugar, 1/4 teaspoon ground cinnamon, and 1 small lemon, juiced to a medium saucepan. Cook over medium heat, stirring occasionally, until the apples are fork-tender and the liquid has thickened to a light syrup, about 8 to 10 minutes.
ADD BUTTER: Remove the saucepan from the heat. Stir in 1 tablespoon unsalted butter until completely melted and the mixture looks glossy. Set the apple filling aside to cool to room temperature, about 15 minutes. Cooled filling seals cleanly and keeps the dough easy to work with.
CUT DOUGH: Unroll both pie crusts from the 1 package 14.1 ounces refrigerated pie crusts (2 crusts) onto a lightly floured surface so the dough lies flat and smooth. Using a 4-inch round cookie cutter or the rim of a glass, cut out circles of dough. Gather and gently re-roll the scraps once until the dough is smooth again to get about 14 rounds total.
FILL EMPANADAS: Spoon about 1 tablespoon of the cooled apple filling onto one half of each dough round, keeping the filling centered and leaving a 1/4-inch border of bare dough around the edge for sealing. Drizzle about 1/2 teaspoon of caramel sauce (1/4 cup caramel sauce total) over the apples on each round.
SEAL AND CRIMP: Fold the dough over the filling to form a half-moon shape. Press the edges firmly with the tines of a fork to seal, working all the way around the curve until no gaps remain. The fork marks create a tight seal and a classic crimped look.
BRUSH AND TOP: Place the sealed empanadas on the prepared baking sheet. Brush the tops with 1 large egg, beaten until evenly coated and shiny. Sprinkle each empanada with a pinch of granulated sugar (2 tablespoons granulated sugar total) for a golden, crackly finish.
BAKE: Bake until the tops are deep golden brown and the edges are crisp, about 15 to 20 minutes. The crust should feel firm when you tap it lightly.
COOL AND SERVE: Let the empanadas rest on the baking sheet for 5 minutes before moving them to a wire rack. The filling will be very hot right out of the oven. Serve warm for the flakiest, most tender crust.
Notes
MAKE-AHEAD: Prepare the apple filling and caramel sauce up to 2 days in advance and store separately in airtight containers in the refrigerator. Let both come to room temperature before assembling and baking.STORAGE: Store leftover empanadas in an airtight container at room temperature for up to 3 days, or refrigerate for up to 5 days. The crust stays crispiest at room temperature.FREEZING: Freeze baked empanadas in a single layer on a baking sheet until solid, about 2 hours, then transfer to a freezer-safe bag. Stays at peak quality for about 1 month. Safe to eat for up to 3 months, though the crust texture starts to soften past that first month. Reheat from frozen in a 375 degree F oven for 12 to 15 minutes until the filling is heated through and the crust is crisp.REHEATING: Warm empanadas in a 350 degree F oven for 5 to 8 minutes until the crust is crisp again and the filling is heated through. The microwave works in a pinch (30 seconds), but the crust turns soft.INGREDIENT TIP: Homemade caramel sauce works best because it is thicker than most store-bought versions. If using store-bought, choose a thick variety and use slightly less so the filling stays contained during baking.