Keep a fine-mesh strainer over a large bowl and line the strainer with a muslin cloth.
Transfer yogurt to the strainer and keep the bowl in the refrigerator for 12-18 hours. If using Greek yogurt, then you can reduce the time to 6-7 hours.
The liquid will drip from the yogurt making it thick and creamy. The thick yogurt that is collected now is called CHAKKA.
Discard the liquid or drink it.
Soak The Saffron
Stir together milk and saffron strands in a small bowl and refrigerate for 3-4 hours.
Make The Matho
Transfer the thickened yogurt to a medium mixing bowl.
Add powdered sugar, mango pulp, cardamom powder, and saffron strands soaked in milk to the bowl.
Mix the ingredients using a wire whisk until smooth and creamy.
Refrigerate the mango matho for a few hours. Garnish with slivered nuts. Serve chilled.
Notes
You can mix the ingredients in a stand mixer fitted with a whisk attachment too.