Preheat oven to 350℉.

In a medium bowl, whisk together the flour, baking soda, baking powder, salt, and espresso powder until combined. Set aside.

Heat a skillet to medium heat and add the butter. Melt the butter, and continue to cook until the butter foams up a bit. It will subside, and at this point I like to start whisking. Keep cooking the butter. Light browned specks will begin to form on the bottom of the pan. Keep whisking, and once you see these golden brown specks, remove from heat and keep whisking for 30 seconds to 1 minute. It should have a super nutty and delicious aroma. I like to transfer it to a bowl so it doesn't keep browning and potentially burn. Let cool for 15-20 minutes.

Once butter is cooled, in a medium bowl, whisk together the sugar and butter until smooth, then add the eggs and vanilla and whisk again until combined. Add the dry ingredients and stir until combined. Fold in the chocolate chips.

Spoon dough onto baking sheet in about 2 tablespoon sized balls and bake for 12-14 minutes until lightly golden on the edges.

Sprinkle with sea salt if desired!