Ingredients

Method

1. 1

   Preheat your oven to 350°F (175°C). Generously grease a 10" or 12" cast iron skillet with butter and set it aside.

2. 2

   In a saucepan over medium-high heat, melt 171g of butter. Continue to cook, stirring continuously, for about 5-8 minutes until it turns a deep golden amber color and has a nutty aroma. Immediately pour the browned butter into a large bowl to stop the cooking process and allow it to cool for 10-20 minutes.

3. 3

   While the butter cools, prepare the filling. In another large saucepan over medium-high heat, combine 28g butter, the diced apples, light brown sugar, maple syrup, cinnamon, apple pie spice, and a pinch of salt. Cook, stirring occasionally, for about 10 minutes until the sugar melts and the apples begin to soften. Covering the pan for a few minutes can help steam the apples.

4. 4

   In a small bowl, mix the cornstarch and water to create a slurry. Pour this slurry into the apple mixture, stir well, and continue to cook for another 1-2 minutes until the filling thickens. Remove from the heat and stir in the vanilla. Set aside to cool.

5. 5

   In a medium bowl, whisk together the all-purpose flour, oats, baking soda, 2g of cinnamon, and 3g of salt.

6. 6

   Once the brown butter has cooled slightly, add the brown and granulated sugars to it and whisk until combined. Whisk in the eggs and egg yolk, followed by the vanilla, until the mixture is fully combined and lighter in color.

7. 7

   Add the dry ingredients to the wet ingredients. Use a spatula or wooden spoon to mix until just combined. Fold in the white chocolate chips, butterscotch chips, and optional toffee bites until evenly distributed.

8. 8

   Press half of the cookie dough into the bottom of the prepared skillet in an even layer. Spread about 3/4 of the apple pie filling over the dough. Reserve the remaining filling for serving. Scoop the rest of the cookie dough on top of the apple filling and gently press it down.

9. 9

   Bake for 25-30 minutes. The edges should be golden brown, the top crinkly, and the center puffed but still gooey. The skillet will continue to bake after being removed from the oven. For a more well-done cookie, bake for a few minutes longer.

10. 10

    Remove the skillet from the oven and let it cool for at least 10-15 minutes. Serve warm, topped with a scoop of vanilla ice cream, a drizzle of the reserved apple pie filling, and a sprinkle of flaky sea salt.