In a medium saucepan, heat the oil over medium heat. Add the onion, tomatoes, turmeric, cumin, coriander, and salt (if using) and cook, stirring, until the onion is translucent.

Rinse the brown rice and moong dal in a fine mesh sieve and drain, then add them to the pan. Add water—use 2 ½ cups for a thicker consistency (which will be easier to form into balls) or 3 ½ cups for a thinner consistency.

Bring the water to a boil, then reduce the heat to low/medium. Cover and simmer until rice and dal are soft, about 40 minutes.

The khichdi may not look like it will hold together in a ball, but it will! To form balls, let the khichdi cool, then refrigerate it for a couple of hours; it will thicken as it cools. Scoop roughly 1 tablespoon portions of khichdi with your hands and roll into balls. The khichdi balls can be eaten cold or microwaved for 30 to 45 seconds to serve warm. Alternately, you can just serve khichdi in a bowl without rolling it into balls.