Update 1/13/17: For an improved recipe, replace the 1/2 cup shortening with 3/4 cup softened unsalted butter. (topsecretrecipes.com)
Using a wooden spoon, creamed 100g of softened unsalted butter with 200g cardamom sugar (golden caster) in a large mixing bowl until the the mixture was light and well combined. (tinandthyme.uk)
In a mixing bowl add in softened unsalted butter and sugar. (eugeniekitchen.com)