In a medium saucepan add brown sugar, granulated sugar, butter, egg yolks, and evaporated milk. Stir to combine and bring the mixture to a low boil over medium heat. Stir constantly for several minutes until the mixture begins to thicken.
Remove from heat and stir in vanilla, nuts and coconut.
For the chocolate frosting:
Melt butter. Stir in cocoa. Alternately add powdered sugar and milk, beating to spreading consistency. Add small amount additional milk, if needed. Stir in vanilla.
Pipe chocolate frosting along the outside edge of a chocolate cupcake. Spoon coconut frosting in the center.
Make ahead Instructions: Bake cupcakes one day in advance. Allow to cool completely and store in refrigerator until ready to frost. Or make cupcakes several days in advance and freeze.Freezing Instructions: To freeze frosted cupcakes, Allow the cupcakes to cool completely, Add frostings and place cupcakes on a sheet pan. Cover loosely with plastic wrap and freeze for a few hours. Once well frozen, transfer them to an airtight container and freezer for 2-3 months. Thaw at in the fridge overnight.Unfrosted cupcakes can be frozen up to 3 months.