Roast the Green Mango (2) with its skin intact on a gas stove on low flame. Occasionally turn the mango so that it gets roasted evenly. Roast till the skin turns black. Make sure the mango is cooked through.
Take the roasted raw mango off flame and remove the burnt layer. Cut the mango into pieces and place it in a blender. Then, add the Fresh Mint Leaves (10), Rock Salt (1 teaspoon), Roasted Cumin Powder (1 teaspoon), Ground Black Pepper (1 teaspoon) and Salt (1/2 teaspoon).
Once all the ingredients are placed in mixture add Caster Sugar (4 tablespoon) and 1/2 cup of Water (1/2 cup) in it. Make a smooth paste.
Add some Ice (1/2 cup) and blend again into juice, then add remaining Water (3 cup). Close the lid and blitz into smooth juice.
Serve cold in glasses, garnished with additional mint leaves if desired for decoration.