Heat the oven to 325°F. In a medium bowl, combine the browned butter, brown sugar, eggs, cardamom, vanilla extract, salt, baking powder, and baking soda (all the ingredients except the sour cream and flour). Whisk well until slightly thickened. Stir in the sour cream until fully combined, then fold in the flour. Pour the batter into a greased 9-inch round cake pan or similar and bake for 35 to 40 minutes or until a toothpick inserted into the middle of the cake comes out clean. Allow the cake to cool in the pan for 10 minutes before removing to a wire rack. Let cool completely. Make the glaze: combine the powdered sugar and coffee and whisk until smooth. The glaze should be very thick but spreadable (otherwise it will just run all over the cake). Adjust the texture by adding a bit more coffee to thin the glaze out or more powdered sugar to thicken it up. Spread the glaze over the top of the cooled cake and allow to set for 20 to 30 minutes before serving. This cake is best eaten the day it’s made but will keep well for 2 to 3 days in an airtight container at room temperature.