Soak the nuts, cardamom, and fennel seeds in few spoons of milk for an hour. Now add everything (except the milk) in a mixer and make a smooth paste. Mix the milk and stir well. You can use a strainer to make it smoother or drink as it is.
NOTE: It taste good when cold. You can garnish with rose petals and saffron. The paste can be stored for a long time if frozen — just take some out, mix it in milk, and serve!
This is a summer drink. It is very popular in northern India, especially during Holi (usually in March), the festival of colors!