Brown the butter and let it cool

• Melt the butter in a saucepan until browned and nutty.
• Let the browned butter cool for about 15 minutes.

Cream butter and sugars

• Cream the cooled browned butter with the brown sugar and white sugar until smooth.

Add egg and vanilla

• Add the egg and vanilla extract and mix well.

Mix the dry ingredients

• In another bowl, combine the flour, baking soda, salt and espresso powder.

Combine wet and dry

• Add the dry ingredients to the wet ingredients.
• Mix until just combined, then fold in the chocolate.

Chill the dough

• Chill the dough for at least 1 hour, ideally around 3 hours.

Bake the cookies

• Scoop the dough onto a baking tray.
• Bake at 175 °C for 9-11 min until the edges are set and the centers are gooey.