Add all the ingredients to the medium jar of a grinder or food processor and grind to make a smooth powder.
Note - You can also dry roast the ingredients for 3-4 minutes over a low flame before grinding to enhance their flavor even more.
Do not over-grind otherwise, the nuts will release their oil, and the powder will become sticky. Just pulse a few times. Then let the mixture cool down for 5 minutes. Pulse again and keep cooling the mixture in between. Pulse until a powder is made.
Store the powder in an airtight container at room temperature for up to a week. You can also freeze it for upto a year.
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Notes
To make Thandai using Thandai powder, heat milk in a pan over medium heat. Once the milk comes to a boil, add 1 tablespoon of Thandai masala powder per cup of milk and cook for 2-3 minutes for the flavors to seep into the milk. Add sugar to taste and cook for another minute for it to dissolve. Refrigerate the milk for 1-2 hours or until chilled. Strain it using a fine-mesh strainer, nut milk bag, or a muslin cloth. Stir in a few drops of rose water. Garnish with dried rose petals and serve chilled.This recipe is suitable for making 2 to 2.5 liters of thandai and can be scaled up or downas required.Reduce the black peppercorns if you don't like spicy kick.Increase the fennel seeds if making it as a summer drink. It enhances its cooling effect.To make this traditional drink vegan, you can use almond milk instead of dairy milk.