Heat the oven to 350°F to get ready for baking.
Whisk together the flour, baking soda, and salt in a small bowl until combined.
Place the butter in a saucepan over medium heat and cook it, stirring occasionally, until it begins to bubble and turns a light brown, about 5 to 6 minutes; set aside to cool.
In a large bowl, combine the brown sugar and granulated sugar, then mix in the browned butter until just incorporated.
Add the egg, egg yolks, and vanilla extract to the sugar mixture and whisk until the batter is smooth and thick.
Fold the dry ingredients into the wet ingredients gently using a spatula until a dough forms.
Stir in the milk chocolate chips and semi-sweet chocolate chunks, then let the dough rest for 15 to 20 minutes to meld flavors.
Line a baking sheet with parchment paper.
Scoop dough portions about 1/4 to 1/3 cup each onto the sheet, spacing them so only 6 cookies fit per pan.
Bake the cookies for about 10 minutes until the edges turn golden and the centers look slightly soft.
Allow the cookies to cool on the hot baking sheet for 10 minutes to finish cooking, then transfer them to a wire rack to cool completely and enjoy!
