Powder walnuts and almonds in a food processor, and coarsely powder the pistachios separately.
In a deep bowl, take milk powder, powdered walnuts, almonds, and cardamom and mix well.
Take a plate and grease it generously with butter.
In a steel wok, take water, add sugar and bring it to a boil. Keep stirring and let the syrup come to a rolling boil. Test it between the index finger and thumb for one string consistency.
Turn off the heat. Add rose water and stir.
Add milk powder, powdered nuts and cardamom. Stir to get a homogenous mixture.
Empty the mixture into the greased plate and tilt it to spread the mixture uniformly.
Dust with powdered pistachios and press with your hands so that pistachios set into the mixture.