1-First, preheat your oven to 350°F (175°C), and remember to adjust for high altitude by watching the bake time closely. Grease a 10-inch cast-iron skillet to ensure nothing sticks and everything bakes evenly.

2-Next, in a mixing bowl, combine the melted butter with both the granulated sugar and dark brown sugar. Stir until the mixture is smooth and well blended, which helps create that signature chewy texture.

3-Then, add the egg, egg yolk, and vanilla extract to the butter-sugar mix, beating lightly for a creamy result. If you’re going vegan, swap in a flaxseed slurry at this point to keep things simple.

4-In another bowl, sift together the all-purpose flour, corn starch, baking soda, and coarse kosher salt to mix in air and avoid lumps, which is key for high altitude consistency.

5-Gradually fold the dry ingredients into the wet mixture to form a thick dough, being careful not to overmix and keep the texture tender. For more ideas on smooth mixing, check out easy baking tips on the blog.

6-Once mixed, fold in the chocolate chips and optional chopped pecans or walnuts for even distribution and extra flavor bursts.

7-Transfer the dough to the greased skillet, spreading it out to about 1-inch thickness for the perfect bake.

8-Bake for 20-25 minutes until the edges are golden and the center is just set, keeping in mind high altitude might speed things up.

9-Finally, let it cool for at least 10 minutes before serving, perhaps with vanilla ice cream for a delightful finish. Proper storage helps maintain freshness, especially in changing high altitude weather.