Bring 1 cup cream and next 6 ingredients to a boil in a 2 1/2-quart saucepan, reduce heat to medium, and cook until reduced to 1/2 cup. Let curry-lime cream cool to room temperature.
Beat remaining 1/4 cup whipping cream and butter with an electric mixer until light and fluffy. Beat in curry-lime cream, 2 tablespoons at a time. Beat in salt.