Preheat your oven to 350°F (175°C) and prepare two baking sheets with parchment paper.

Melt 12 tablespoons of unsalted butter in a light-colored saucepan over medium heat, stirring it until it forms a deep amber color.

Combine the cooled brown butter with 1.5 cups of dark brown sugar and 0.5 cup of granulated sugar in a mixing bowl and blend until smooth.

Add in 1 large egg, an additional yolk, 1 tablespoon of milk, and 1 teaspoon of vanilla extract, mixing until fully incorporated.

In another bowl, whisk together 2 2/3 cups of all-purpose flour, 1 teaspoon of salt, 1 teaspoon of baking soda, and 0.5 teaspoon of baking powder; fold this mixture into the wet ingredients.

Chop 8 ounces of semi-sweet chocolate into chunks and fold ¾ cup into the dough, reserving the rest for topping.

Form the dough into balls about 2-3 tablespoons each, placing them on the baking sheets and pressing the tops into the reserved chocolate chunks.

Bake for 10-11 minutes until the edges are golden brown and the centers are slightly soft.

Let the cookies cool on the baking sheets for 2-3 minutes, then transfer to wire racks to cool completely.