In a large mixing bowl, combine the melted butter, brown sugar, and granulated sugar. Mix until smooth and well combined.
Add the vanilla extract and eggs to the mixture, one at a time, mixing well after each addition until fully incorporated.
In a separate bowl, whisk together the flour, baking soda, and salt. Gradually add the dry ingredients to the wet mixture, stirring until just combined. Be careful not to overmix.
Fold in the chocolate chips and nuts (if using) until evenly distributed throughout the dough.
Grease a cast-iron skillet (or any oven-safe skillet) with a bit of butter or non-stick spray. Spread the cookie dough evenly in the skillet, smoothing the top.
Bake in the preheated oven for 25-30 minutes, or until the edges are golden brown and the center is slightly soft.
Remove from the oven and allow to cool for about 10 minutes. The cookie will continue to cook a bit as it cools in the pan.
For the ultimate indulgence, scoop some vanilla ice cream on top of the warm cookie before serving.
Notes
Serve the cookie straight from the skillet with a scoop of ice cream on top, and drizzle with chocolate sauce or caramel for an extra touch of sweetness.