Prepare 1 cup Aged Gouda cheese by grating and storing in the freezer for one hour. Prepare 1 3/4 sticks unsalted butter by cutting into 1-inch cubes and storing in the freezer for one hour.
When both the cheese and butter have chilled, make the dough. Whisk together 1 1/3 cups all-purpose flour, 1/4 cup cornmeal, and 3 tablespoons granulated sugar in a medium bowl. Add chilled and grated Gouda cheese and whisk to combine. Add 1 3/4 sticks cubed unsalted butter and use a pastry dough blender to incorporate the butter into the mixture until the butter is completely integrated and the largest pieces only resemble pea-sized crumbs. Drizzle 2 tablespoons of ice cold water over the dough, mixing the water in with the pastry cutter. Add more water (up to 2 tablespoons) if necessary, mixing until the dough just comes together.
Remover the dough from the bowl and form it into 2 equal disks. Wrap each disk in plastic wrap and refrigerate for at least 2 hours. The dough can be refrigerated for up to 2 days or frozen for up to 1 month; thaw in the refrigerator before using.
For the Salted Caramel and Apple Filling and Putting It All Together:
Prepare a 13 by 18 inch baking sheets by lining with parchment paper or a Silpat mat. Set aside.
Peel, core and thinly slice 3 pounds of apples. Place the prepared slice in a medium bowl, and sprinkle 1 cup dark brown sugar over the mixture, tossing to combine. Set aside to allow the apples to macerate.
Remove one disk of dough from the refrigerator and place on a cool, floured surface. Use a rolling pin to roll out the dough into a 13-inch circle. To create a perfect circle, start from the center of the dough and roll outward, rotating the dough 2 to 3 inches after each rule to help create a true circle. Once you've finished rolling out the dough, use an offset spatula to help release the dough from the workspace by running it underneath the dough. Transfer to the freezer and refrigerate for 15 minutes. While the dough is chilling, position a rack in the center of the oven and preheat the oven to 325 (F).
Once the dough is finished chilling, the crust should be cold and firm to the touch. Remove from freezer and use a sharp knife to cut off the very edges of the border, so you're left with a smooth edge. Arrange half of the apples on the dough, leaving a 2-inch border all around. Drizzle 1/2 cup caramel sauce over the apples.
Lift one side of the dough over the apples and press it down over the fruit, making 5 or 6 large pleat folds. Continue around the crostata, creating the pleats and pressing down so they adhere.
Once you've finished making the pleats, place the baking sheet with the crostata back in the freezer and chill for about 15 minutes, or until the crust is cold and firm to the touch.
Use a pastry brush to brush the edges of the dough with 1 beaten egg. Sprinkle 1/2 teaspoon flaky sea salt over the fruit. Bake for 45 to 55 minutes, or until the crust is golden. When the crostata is finished baking, let the crostata cool completely on the baking sheet on a wire rack.
Repeat steps above for the second crostata. The crostatas can be stored, covered at room temperature for up to 2 days.