Begin by melting butter in a non-stick pan over medium-low heat until it turns brown and gives off a rich, nutty aroma, stirring continuously.
Lower the heat to the minimum setting and add the sugars, whisking gently for1-2 minutes to help dissolve them completely.
Removethe pan from heat and let the mixture cool for 5 to 10 minutes until it reachesa warm but not hot temperature.
Add the egg and yolk, whisking vigorously for 1-2 minutes until the mixture turns smooth and light.
Incorporateall the dry ingredients and gently fold with a rubber spatula until nearlycombined.
Gentlyfold in chopped chocolate until it's evenly dispersed, making sure all theflour is well incorporated.
Divide the dough into 8 balls using a 2-inch scoop, avoiding excessive pressure. Optionally, top each ball with a few additional chocolate chunks.
Refrigerate the dough balls for a minimum of 30 minutes, ideally 2 hours or more.
Preheat the oven to 375°F (conventional) and line a large cookie sheet with parchment paper.
Arrange the chilled dough balls on the sheet, leaving at least 3 inches of space between each.
Bake for 10–12 minutes, adjusting time for desired cookie texture—soft and gooey or slightly firmer.