In a medium sized saucepan add the butter and brown it over medium/high heat, takes about 8-10 minutes.
180 g butter
Pour the browned butter into a bowl, and make sure to scrape out all of the brown bits from the saucepan, as that’s all the nutty flavor. Add the instant espresso powder and stir it together. Let it cool down in the refrigerator till room temperature, takes about 30-35 minutes.
1 tablespoon instant espresso powder
Once the butter is room temperature add the brown sugar and granulated sugar and stir it together for about 1 minute.
50 g granulated sugar, 150 g brown sugar
Add the egg and vanilla and mix it in.
1 large egg, 1 teaspoon vanilla extract
Add flour, baking powder, baking soda, and salt and fold it together until just combined. Chop the semi-sweet chocolate and fold it into the batter.
220 g all-purpose flour, ½ teaspoon baking soda, ½ teaspoon baking powder, ½ teaspoon salt, 85 g chopped semi-sweet chocolate or chocolate chips
Using a 2 tbsp/ 1.3 ounce (about 57 g) cookie scoop, scoop out 11 cookie dough balls. Place the pre-scooped cookie dough in the fridge and let them sit in the fridge for 2 hours or overnight.
30 minutes before baking, preheat the oven to 175ºC/ 350ºF conventional oven. Prepare a baking sheet with parchment paper.
Once the 2 hours have passed, add 6 cookie dough to a baking tray lined with parchment paper and bake them for 10-12 minutes. Keep the other cookies in the refrigerator while the others bake.
Once baked, let them cool down on the baking tray for 5 minutes as they still will be soft when they are done. After they have cooled down a bit, use a spatula to lift them onto a cooling rack. To finish them off, sprinkle them with flaky sea salt.