Place the chopped pecans and butter in a large skillet over medium heat. Stir constantly, for 4 to 5 minutes, or until lightly toasted and fragrant. Transfer to a small bowl until needed.

Preheat the oven to 350ºF and grease a 10-inch cast iron skillet with nonstick cooking spray or butter.

In a medium saucepan, melt the butter over medium-low heat. As the butter melts, it’ll start to foam, then turn a clear golden color. Continue to stir the butter, scraping up any browned specks from the bottom of the pan as it starts to brown. It should have a nutty aroma. Once browned and nutty, remove from the heat and pour into a large mixing bowl; cool slightly.

Whisk the flour, baking soda, salt, and cornstarch together in a medium bowl; set aside.

Using a wooden spoon, vigorously stir the sugar into the brown butter until smooth and combined, about 1 minute. Stir in the eggs and vanilla. Add the flour mixture, stirring until just incorporated. Stir in the oats, chocolate chips* and buttered pecans. Press dough evenly into the skillet, and bake in the oven for 20-25 minutes, or until the edges are lightly browned and the center is set.

Allow to cool for at least 20-30 minutes. Slice and serve with a scoop of ice cream, if desired.