Ingredients
Equipment
Method
- Preheat your oven to 350 degrees F. Rub about a teaspoon of softened butter all over the inside of a 10-inch cast iron skillet, including up the sides, and set it aside.
- In a large bowl, whisk the melted butter and brown sugar together until smooth and glossy, about 1 minute. Add the egg and vanilla and whisk again until fully combined.
- Add the flour, oats, cinnamon, baking soda, and salt to the bowl. Switch to a rubber spatula and stir everything together until just combined and no dry streaks remain. Do not overmix.
- Fold in the diced apple and pecans if using. The dough will be thick. Scrape it all into the prepared skillet and press it into an even layer with the spatula or your clean fingertips, spreading it all the way to the edges.
- Bake on the center rack for 22 to 26 minutes. The edges should be set and deep golden brown, and the top should look matte and dry. The very center may still look slightly soft and that is exactly right. Do not wait for the center to look fully baked or it will be dry.
- Set the skillet on a wire rack and let it rest for 5 minutes. The residual heat from the cast iron will finish cooking the center during that rest. Serve warm, cut into wedges directly from the skillet, with vanilla ice cream on top.
Notes
A 10-inch skillet gives you a thick, gooey center. A 12-inch skillet will produce a thinner, crispier cookie that bakes closer to 18 to 20 minutes. Check it early if you use a larger pan.
