Take curd in a strainer and place strainer on a bowl or other vessel and leave for 30 mins so that water is separated. You can use muslin cloth also to squeeze out water.

Now add powdered sugar in thick curd, add little(as shown in picture) food colour, or kesar dipped in water.If you want, you can keep it white also.

Now with a spoon, mix it well, till curd becomes smooth.