Melt the butter in a small saucepan over a medium heat until it begins to foam and sizzle. Stir constantly until brown specks appear and it smells nutty, then pour it into a large bowl.

Let the browned butter cool for at least fifteen minutes so it is no longer hot to touch. This is a very important step to ensure your sugar does not melt too quickly and get greasy.

Add the dark brown sugar and white sugar to the cooled brown butter in your large mixing bowl. Whisk or beat them together for about two minutes until the mixture looks like wet, dark sand.

Mix in the egg, extra yolk, bourbon, and vanilla extract until the batter is very smooth and creamy. The bourbon adds a wonderful smoky depth that balances the sweet chocolate and the salty toasted pecans.

In a medium bowl, whisk the flour, baking soda, and sea salt together until they are perfectly blended. Using a separate bowl ensures the baking soda is spread evenly throughout all of your cookie dough.

Slowly add the dry flour mixture into the wet butter mixture using a large rubber spatula or spoon. Stir gently just until you see no more white flour streaks left in the dark brown dough.

Gently fold the chocolate chunks and toasted pecans into the thick dough until they are evenly spread out. Use a folding motion to keep the dough tender and prevent the cookies from becoming very tough.

Cover the bowl with plastic wrap and chill the dough in the fridge for at least one hour. Chilling helps the flavors deepen and prevents the cookies from spreading too flat on the hot baking sheet.

Preheat your oven to 350°F and scoop rounded tablespoons of dough onto your lined baking sheets today. Bake for ten to twelve minutes until the edges are golden brown but the centers are soft.

Remove the pans from the oven and sprinkle each hot cookie with a tiny pinch of flaky salt. Let them cool on the pan for five minutes before moving them to a wire cooling rack.