Grease a pan that’s approximately 9×6 inches.Heat a heavy bottom pan on medium to low heat. Once hot, add in the butter and 1/2 cup of milk. Let the butter melt.Once the butter melts, add in the milk powder stirring constantly. Once the powder is incorporated with milk, gradually add in the powdered sugar.If there are bits of dry powder left, add in the three tablespoons of milk. If you need to add more milk, add a tablespoon at a time. At this stage the mixture should have a paste like consistency.While continuously stirring, cook the mixture for 8-9 minutes or until it easily leaves the surface of the pan. The mixture should look like a dough.Turn the heat off and add vanilla essence, cardamom, and a tablespoon of pistachios. Mix everything well. Spread the mixture evenly on the greased pan and top the remaining tablespoon of pistachios.Let the burfi set for at least three hours. Once set, it can be stored in an airtight container at room temperature for up to seven days.