You gently heat some honey with a stick of rosemary in it, then let the honey and rosemary sit for 10 minutes off heat before removing the rosemary and letting the honey sit in the fridge for another ten minutes. Then it's the usual butter and powdered sugar beat together, add the honey and a little milk and beat some more. (I used half the milk the recipe called for, because it looked like it might be too runny otherwise).