Preheat your oven to 350°F (175°C).

In a saucepan, melt the butter over medium heat until it browns, stirring frequently. Let it cool slightly.

In a large bowl, combine the brown sugar, granulated sugar, and browned butter. Mix until well combined.

Add in the egg and vanilla extract, mixing until smooth.

In another bowl, whisk together the flour, rolled oats, baking soda, and salt. Slowly pour this mixture into the wet ingredients, stirring until just combined.

Fold in the brewed espresso or coffee.

Scoop tablespoons of dough onto a baking sheet lined with parchment paper, spacing them about 2 inches apart.

Bake for 10-12 minutes until the edges are golden and the centers are slightly soft.

Allow cookies to cool on the baking sheet for a few minutes before transferring them to a wire rack.

For the icing, whisk together powdered sugar and a bit of espresso until smooth. Drizzle over cooled cookies before serving.