Melt the sugar over medium high heat in a large pot. Whisk the sugar as it melts and cook until it becomes a deep amber color. Add the butter and stir it in until melted. Pour in the light cream and whisk until you get a smooth sauce. Remove from heat and let cool.
In a mixer, beat butter until lightened and fluffy. Reduce speed to low and add powdered sugar. Mix until thoroughly combined.
Add the caramel. Beat until light and airy, and completely mixed. Mixture should be ready to use without refrigeration. If mixture is runny, refrigerate for 15 minutes.