1 cup berries
1 Tbsp Chelsea White Sugar
1 cup unsalted butter, room temperature
2-3 cups Chelsea Icing Sugar, sifted
1 tsp vanilla

In a saucepan over medium heat, cook the berries and Chelsea White Sugar together. Use a wooden spoon to break the berries apart.
Simmer until significantly reduced — you should have about 1/3 cup of liquid.
Remove from the heat and let cool before proceeding.
With a mixer, cream the butter together with the cooled berries and 1 cup of Chelsea Icing Sugar.
Mix until completely smooth, then add the vanilla and remaining Chelsea Icing Sugar to your desired consistency.