Sift 1 cup gram flour through a fine mesh into a mixing bowl to remove any lumps.

Add 1/2 teaspoon salt, 1/4 teaspoon turmeric powder, and 1 teaspoon sugar to the flour and whisk to combine.

In a separate bowl, whisk 1/2 cup yogurt and 1/4 cup water until smooth; stir in 1 tablespoon lemon juice, 1 teaspoon grated ginger, and 1 finely minced green chili.

Combine the wet mixture with the dry ingredients and stir until you have a smooth, thick but pourable batter.

Lightly oil a round cake mold with 1 teaspoon oil, coating the bottom and sides evenly.

Just before pouring, fold 1/2 teaspoon baking soda into the batter with 8 to 10 gentle strokes.

Pour the batter into the prepared mold and smooth the top with a spatula.

Bring water to a rolling boil in a steamer pot or pressure cooker; place the mold on the steamer stand and steam, covered, for 12 to 15 minutes until a toothpick comes out clean.

Remove the mold and let it cool for 2 minutes; run a knife around the edges and invert the dhokla onto a cutting board.

For the tempering, heat 2 tablespoons oil in a small pan over medium heat; add 1 teaspoon mustard seeds and let them pop, then add 8 to 10 curry leaves, 1 split green chili, and a pinch of asafoetida; toast for about 10 seconds until fragrant.

Pour the hot tempering over the warm dhokla, cut into pieces, and serve immediately with green chutney or tamarind chutney.