In a mixer jar, add 2½ cups (250 g) besan (gram flour), salt to taste, ¼ tsp turmeric powder, 2 chopped green chilies, 1-inch ginger, a pinch of hing (asafoetida), 3 tbsp lemon juice, 2 tbsp sugar, 2 tbsp oil, and 1½ cups (300 ml) water. Grind until you get a smooth batter. The batter should have a medium-thick, ribbon-like pouring consistency.
Transfer the batter to a mixing bowl. Cover and let it rest for 10 minutes.
Add 1 tsp baking soda and a little water to the batter. Mix vigorously for 1 minute until the batter becomes light, frothy, and creamy.
Immediately pour the batter into a greased dhokla tin or steaming bowl.
Add 3–4 cups of water to a steamer and place a stand in the center. Preheat the steamer for 5 minutes.
Place the dhokla tin on the stand. Cover and steam the dhokla over a medium-high flame for 20 minutes, or until a toothpick inserted into the center comes out clean.
Once the dhokla is fully cooked, allow it to cool completely. Then gently demould it.
To prepare the tempering, heat oil in a pan. Add 1 tsp mustard seeds, 3–4 chopped green chilies, and a few curry leaves. Sauté for a few seconds until aromatic.
Add ½ cup water and bring it to a boil. Add 2 tbsp sugar and stir until it dissolves completely.
Pour the hot tempering evenly over the cooled dhokla and garnish with chopped coriander leaves.
Serve the soft and spongy Nylon Khaman Dhokla with green chutney.