Grease a pan that fits your steamer and bring water to a boil in the steamer. Crush 1 piece of ginger, 1½in / 4cm long, and 1½ teaspoons of chopped green chilies to a paste.
Whisk 1½ cups of chickpea flour (besan), 1 cup of water, and the paste with 1 tablespoon of sugar, 1 teaspoon of salt, and 1 tablespoon of oil.
Add 2 pinches of turmeric, 1 pinch of asafoetida, and 1½ tablespoons of lemon juice. Whisk into a smooth, thick, lump-free batter.
Quickly stir in 1½ teaspoons of fruit salt (Eno) and pour the foaming batter into the pan at once. Steam for 12-15 minutes.
Let it cool enough to unmold, then cut into squares.
Heat 2 tablespoons of oil in a small pan and add 1 teaspoon of mustard seeds. When they crackle, add 10 curry leaves, then 2 teaspoons of white sesame seeds, without browning them.
Add ⅓ cup of water, bring to a boil, and pour over the khaman.
