Melt 2 Tbs. butter in a skillet.
Add coconut and stir until golden brown.
Remove about half the coconut; set aside.
Melt remaining butter in skillet with coconut.
Add brown sugar.
Cook and stir over low heat 2 minutes, or until blended.
Then add milk; bring to a boil.
Remove from heat.
Gradually add confectioners' sugar until it's the right consistency to spread, beating well after each addition.
Spread on cake.
Sprinkle with remaining coconut.