Soak the Dal: Pick over the moong dal to remove any debris.
Rinse it thoroughly, place it in a large bowl, and cover with at least 2 inches of water.
Let it soak for 8 hours or overnight.
Once soaked, drain the dal completely in a fine-mesh strainer.
Make the Tomato Pulp: Combine the quartered tomatoes and 1/3 cup (720 ml) of water in a small saucepan.
Cover and simmer over medium heat for 10 minutes until the tomatoes are very soft. Press the softened tomatoes and their liquid through a fine-mesh strainer into a bowl, using a spoon to extract as much pulp and juice as possible.
Discard the skins and seeds left in the strainer.
Cook the Tomato Masala: Heat the ghee or oil in a small saucepan over medium-high heat.
When hot, add the cumin seeds and fry until they darken and become fragrant. Carefully pour in the tomato pulp and add the salt.
Stirring frequently, cook the mixture until all the liquid has evaporated and the oil begins to separate from the thick tomato paste.
Remove from heat and set aside to cool completely.
Grind the Dal: In a food processor or high-powered blender, grind the drained dal into a smooth, thick, and airy paste using as little water as possible. Scrape down the sides periodically. The final paste should be perfectly smooth and fluffy.
Combine and Rest: Transfer the dal paste to a large mixing bowl.
Add the completely cooled tomato masala, garam masala, baking soda, cayenne pepper, and chopped green chilies. Gently fold everything together until just combined. The paste should be thick enough to hold its shape. If it seems too loose, add the optional flour one tablespoon at a time until it thickens.
Cover the bowl and let it rest in a warm place for 4 hours.
Form the Dumplings: Lightly grease a few large baking sheets or dehydrator trays.
Using two teaspoons or your fingertips, drop scant teaspoon-sized dollops of the batter onto the prepared trays, leaving a little space between each one.
Dry the Badi: Dry the dumplings using one of the following methods until they are completely hard and brittle.
Sun-Drying: Place trays in direct, strong sunlight for 2-4 days.
Cover with a thin net to protect from insects and bring indoors at night.
Dehydrator: Dry at 125°F / 52°C for 10-15 hours.
Oven: Set your oven to its lowest temperature (around 170°F / 75°C). Prop the oven door open slightly to allow moisture to escape.
Bake for 8-12 hours, checking periodically.
Store the Badi: Once the badi are completely dry and cooled, store them in a well-sealed, airtight container at room temperature. They will keep for many months.