To make sweet punjabi lassi, combine the curd and powdered sugar in a blender or mixer and whisk well till smooth.
Refrigerate it for 30 minutes.

Pour into two individual serving glasses and garnish with some ice cubes or some chopped dry fruits
serve immediately.

Do not over blend the mixture as butter may start flowing out. If you are interested, add a flake of saffron while blending the mixture. Instead of blender or mixer, you can opt the traditional way of whisking by using hand whisk.
The amount of water/milk can be adjusted based on the consistency desired.
Curd and milk or water should be absolutely chilled.
Lassi is usually thicker than chaas or Indian buttermilk. So add chilled milk or water only as needed to bring the curd to consistency.