½ tsp Eno Fruit Salt (you can find this at any Indian grocery store-- it's primarily meant to fight indigestion)
Salt to taste
1 tsp oil to sputter the mustard seeds
2-3 tsp mustard seeds
½ cup finely chopped coriander leaves
¼ cup shredded coconut
A pinch of cayenne pepper to sprinkle on the dhokla (optional)
Soak the rice and the dals together for about 8 hours or overnight.
Drain, then blend with some water to make a rather smooth paste. You will need a fairly powerful blender for this, like a Vitamix or one of those hardy Indian blenders. I just put it into my dosa grinder which does a great job.
Add the tofu and lemon juice and salt and blend a little more until everything's nicely mixed.
Set aside for 2-6 hours to ferment. I would recommend two hours if you don't want your dhokla sour-- Desi and I prefer it that way.
Grease a baking dish or any dish with sides at least 2-3 inches high. Heat about 1 inch water in a pan that the dish will fit into and let it come to a boil.
Pour the batter about 1 inch deep in the greased dish. Now add the Eno Fruit Salt and stir gently, in a single direction, until just mixed. You will start to see the dough bubble and fluff up right before your eyes.
Carefully place the pan inside the boiling water, reduce to a simmer, and sprinkle some cayenne on top. Cover the pan with a snug lid, and let the dhokla steam at least 10-15 minutes or until a toothpick inserted in the center comes out clean.
Remove, allow it to cool a little, and then cut into squares.
Heat the oil and sputter the mustard seeds. Pour over the dhokla pieces. Sprinkle the coriander and coconut on top.