In a medium saucepan, melt the butter over medium heat.
Brown sugar, 1/4 cup cream, and salt should be incorporated.
Stirring frequently, proceed cooking until the caramel mixture begins to simmer and froth. After two minutes of simmering, remove from fire.
In a large basin or the bowl of a stand mixer, pour the caramel. Cool for a minimum of thirty minutes.
Combine the remaining 1/4 cup of heavy cream and 3 cups of powdered sugar once the caramel has cooled. Stir until smooth.
Add additional powdered sugar as necessary to achieve a buttercream-like consistency for the icing.