First blanch the almonds. You can soak them overnight or soak in hot water for 15-20 minutes and then peel off the skin. It would easily come off.
Transfer the blanched almond to a blender along with peppercorns, fennel seeds, poppy seeds, watermelon seeds and cardamom pods.
Grind to a smooth paste. You may add little milk for grinding if needed. I didn't add any. This is the thandai masala, set it aside.
Add milk to a heavy bottom pan on medium heat. Stir in between and let it come to a slight boil.
While the milk is getting heated up, remove 2 to 3 tablespoons of the hot milk from the pan and transfer to a small bowl. Crush saffron strands between your fingers and add it to the hot milk. Let it sit until it gets a nice yellow color.
Once milk comes to a boil, lower the heat and add the thandai masala to it. Use a wire whisk to mix it all together.
Then add the sugar and mix until it dissolved. Turn off the heat.
Add the saffron-milk mixture to the pan and stir. Let the thandai sit like this for 30 minutes.
After 30 minutes, add rose water and stir. Let it sit for another 30 to 60 minutes. This is important for the milk to absorb all the flavors of the spices before we strain it.
After it's been sitting for a while and all the milk has absorbed all the flavors, strain the thandai using a sieve into a pitcher.
Press the solid thandai masala that collects into the sieve with the back of a spoon as you strain it- this is to get the maximum flavors out of the spices into the thandai.
Transfer the pitcher to a refrigerator and chill, preferably overnight.
To serve, pour thandai into glasses and garnish with sliced nuts like pistachios, almond, rose petals and saffron strands!
Thandai should be served chilled. So chill it for 4 to 5 hours before serving, preferably overnight.You can make thandai few days in advance. Keep it refrigerated.