Ingredients:

  • 2 1/4 cups All-Purpose Flour
  • 1 1/2 cups Rolled Oats (Jumbo or Old-Fashioned)
  • 1 cup Light Brown Sugar, packed
  • 1/2 cup Granulated Sugar
  • 1 teaspoon Baking Powder
  • 1/2 teaspoon Fine Sea Salt
  • 1 cup Unsalted Butter, very cold and cubed
  • 5 large Apples (e.g., Braeburn or Honeycrisp), peeled, cored, and diced
  • 1/4 cup Granulated Sugar (for filling)
  • 1 tablespoon All-Purpose Flour (for filling)
  • 1 teaspoon Ground Cinnamon
  • 1/4 teaspoon Ground Nutmeg
  • 1 tablespoon Lemon Juice
  • Pinch of Fine Sea Salt (for filling)
  • 1/2 cup Thick Salted Caramel Sauce
  • 1/4 teaspoon Coarse Flaky Sea Salt (for sprinkling)

Instructions:

  1. Prepare the Pan and Oven: Preheat oven to 350°F (175°C). Line the 9x13 inch pan with parchment paper, ensuring a good overhang on the two long sides to act as 'slings'.
  2. Make the Crumble Mixture: In a large bowl, whisk together all dry ingredients for the crumble (flour, oats, sugars, baking powder, and salt). Cut the cold, cubed butter into the dry ingredients using a pastry cutter, until the mixture resembles coarse, wet sand with pea-sized chunks of butter remaining. Measure out 2 cups of the crumble mixture and set it aside for the topping.
  3. Form and Chill the Base: Press the remaining crumble mixture evenly and firmly into the bottom of the prepared pan. Use the base of a measuring cup or glass to ensure it is firmly packed and flat. Place the pan in the refrigerator to chill for 30 minutes.
  4. Prepare the Spiced Apple Filling: Combine the diced apples, sugar, flour, cinnamon, nutmeg, lemon juice, and salt in a small saucepan. Cook over medium heat for 5-7 minutes, stirring occasionally, just until the apples start to soften slightly and the mixture thickens. Remove from heat and allow to cool for 5 minutes.
  5. Assemble and Bake: Remove the chilled pan from the refrigerator. Evenly spread the cooled apple filling over the shortbread base. Drizzle the salted caramel sauce generously over the apple filling. Sprinkle the reserved 2 cups of crumble mixture evenly over the top, making sure to cover most of the caramel. Sprinkle with the coarse flaky sea salt. Bake for 40 to 45 minutes, or until the topping is golden brown and the filling is bubbling lightly at the edges.
  6. Cool and Cut: Remove the pan from the oven and place it on a wire rack. Crucially, allow the bars to cool completely (1.5 to 2 hours) before attempting to lift them out of the pan. Once cooled, use the parchment paper slings to lift the entire slab onto a cutting board and cut into 12 even bars.