Place the butter in a saucepan over medium heat. Heat the butter, stirring constantly, until it foams, turns a dark amber color, and smells nutty. The little flecks at the bottom of the pan should turn a dark brown color. Pour into a heat proof container and place in the freezer for about 20 minutes, or until solid but not frozen.
Add the chilled butter to the bowl of a stand mixer fitted with the paddle attachment. Beat until creamy. Add the brown sugar and white sugar, and beat for 1 minute. Add the egg and vanilla and beat until combined.
In a separate bowl, whisk together the flour, baking soda, malted milk, and salt. Do not skip this step. Add the dry ingredients to the wet ingredients and mix until just combined. Do not over mix. Fold in the chocolate chips.
Preheat the oven to 350 ℉. Roll cookie dough into 3 tbsp balls. Line two baking sheets with parchment or silicone mats. Evenly space 6 cookies per baking sheet. Chill for 15-20 minutes before baking.
Bake for 12-14 minutes, until the edges are golden and the centers are still soft. Sprinkle the top of each cookie with flaky sea salt. Let cool on the baking sheet undisturbed for 3-5 minutes before transferring to a cooling rack. Enjoy!