In a blender, combine 3 cups buttermilk, cardamom seed, rosewater, and ice. Whirl until ice is finely crushed; pour into a pitcher.
Stir in remaining buttermilk, 1 1/3 cups water, and sugar and salt to taste.
Pour into glasses and garnish with mint sprigs.
Servings 0
* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.