Cream the butter and brown sugar together until light and fluffy.
Add eggs one at a time, mixing well, then stir in vanilla extract.
Whisk together flour, baking soda, and kosher salt in a separate bowl.
Gradually mix the dry ingredients into the wet until just combined.
Fold in chocolate, coconut, and peanuts gently.
Incorporate sweetened condensed milk until evenly distributed.
Chill the dough for at least 30 minutes covered with plastic wrap.
Preheat the oven to 350°F (175°C).
Scoop dough onto baking sheets leaving space for spreading. Bake for 10-12 minutes.
Cool on sheets for 5 minutes before transferring to wire racks.