I came up with this recipe while searching the internet for a lighter version coconut cupcake. I found a recipe for Coconut-Lime cupcakes and modified it slightly to make it lighter. Then I basically used my Grandmother's 7 minute icing recipe also modified (by adding mini-marshmallows). I had some toasted coconut and walnuts left over from another recipe and this was the result! Very yummy!
In a separate bowl, sift flour, salt, baking powder and baking soda together.
Slowly beat in sour cream and flour alternately into butter mixture.
Spoon into muffin tins, about 2/3 full.
Bake about 20 to 25 minutes. Cupcakes are done when they spring back to the touch and are slightly golden brown on top.
Cool before frosting.
While cupcakes are cooling, put sugar, Karo and water in medium boiler on stove. Cook on medium-high, stirring constantly until boiling. Boil until mixture spins a thread when poured from a spoon. Turn off heat, add mini-marshmallows, don't stir. Meanwhile beat egg whites until peaks form. Pour hot syrup over egg whites beating on high constantly. Be careful! Syrup is very hot! Beat for another two minutes. Add pinch of salt and vanilla and stir. If frosting looks too runny, put in fridge to cool before frosting cupcakes.
Frost cupcakes, add a pinch of coconut-walnut topping to each one. (I always process the walnuts and coconut in a mini chopper before toasting)