Burfies, which are like a dense fudge, are made from a wide range of ingredients from chocolate to figs. They can be picked up with one’s fingers and the texture varies from being soft and moist to quite dense and dry. As they are quite sweet, they keep well for 3 to 4 days at room temperature, and for up to a week in the fridge. They are often decorated with edible silver or gold foil called “varq," which can be bought from some Indian stores.
Put the condensed milk in a heavy-bottomed saucepan over low heat and cook for 10 to 15 minutes, stirring constantly, until the mixture thickens and comes away from the sides of the pan.
Stir in the butter, cashew nuts, and cardamom, then remove from the heat. You should be able to move the mixture easily with the back of a wooden spoon.
Grease a flat dish with the extra butter. Pour the burfie mixture in and smooth the surface with a spatula.
Let cool and set for 2 to 3 hours, then cut into about twelve 1-inch squares or diamonds and decorate with edible silver foil (if using).