Heat a small saucepan over medium-low heat and add butter. Whisk constantly until melted, then continue to whisk as bubbles form, the butter begins to foam, and eventually brown bits appear in the bottom of the pan. This will take about 5 minutes. As soon as the brown bits appear, remove from heat. Let cool for 10 minutes.
In a large bowl combine brown butter, vanilla extract, ground cardamom and powdered sugar. Whisk until the mixture comes together then add in 1 tablespoon of milk, continuing to mix for 3-4 minutes. Gradually add mmore milk until you reach the desired consistency. Drizzle the glaze over the cooled cookies.
Recipe by the modern barista at https://themodernbarista.com/index.php/2016/02/27/heal-the-bay-blend-with-spicy-oatmeal-cookies/