Make the brown sugar glaze. Melt the butter in a saucepan and whisk in the brown sugar, pinch of nutmeg and milk. Simmer for a few minutes until the sugar has dissolved and the mixture thickens. Add the powdered sugar and whisk until smooth. Allow the glaze to cool a little, but while it is still warm, pour the glaze over the cooled cake allowing some to drip down the sides. If the glaze drips to fast, allow it to cool a little more.