Grease a steamer pan with 2 to 3 teaspoons of oil.
Take besan in a mixing bowl or pan.

Add turmeric powder, asafoetida, lemon juice, ginger paste, green chilies paste, sugar, oil and salt.

Add 1 cup water or as required to make thick yet flowing water. The amount of water required depends on the quality of flour, so add as required.

Stir to a smooth thick batter without any lumps.
The batter should be thick yet flowing. A quick tip is that if the batter become thin, then add 1 to 2 tablespoon besan.

Bring to a boil 2 to 2.5 cups of water in a steamer pan or electric cooker or a stove-top pressure cooker.
The amount of water to be added depends on the size of the steamer or pressure cooker.

Now add the eno or fruit salt to the batter.
Stir briskly and quickly. The fruit salt should be mixed evenly with the batter. Or else you get uneven texture in the khaman.
The batter would froth and become bubbly, so you have to be quick.
Pour the batter in the greased pan.

Place the pan in a steamer The water should already be boiling or hot when you place the pan with the batter.
Steam for 15 to 20 minutes.
To check the doneness, insert a toothpick and if it comes out clean, the khaman is done.

Invert the pan. If greased well, the khaman will easily get inverted on the plate. Slice and keep aside.

In a small pan, heat oil.
Add mustard seeds and let them to crackle.
When the mustard seeds are crackling, add the cumin seeds (optional), curry leaves and chopped green chilies (optional).
Stir and then add sesame seeds.
Fry the sesame seeds for some seconds but do not brown them.

Then add water. Be careful while adding water as the mixture sizzles. You can switch off the heat when adding water.
Add sugar. Stir and allow the tempering mixture to come to a boil. Make sure that the sugar has dissolved in the water.
Then pour this tempering mixture evenly on the steamed and sliced khaman.
Garnish with chopped coriander seeds and grated coconut.