In a saucepan, melt the butter. Once it is melted, add the brown sugar. Stirring constantly, bring the mixture to a boil, and let it boil for 2 minutes.
Lower the heat, and add the milk slowly. Bring the mixture just back up to a boil then remove from heat.
Allow the mixture to cool until it is lukewarm.
Gradully stir in the powdered sugar, using a hand mixture to whip the frosting, making it light and creamy. Add enough frosting until your desired thickness.
If the frosting gets thicker just sitting on the counter, add a bit of vanilla extract.
Add food coloring if desired!
