Soak the Dal: Rinse the urad dal thoroughly.
Place it in a large bowl, cover with at least 1½ inches of water, and let it soak for 8 hours or overnight.
Drain the dal completely in a fine-mesh strainer.
Toast and Grind Spices: In a dry skillet over medium-low heat, toast the coriander, cumin, and fennel seeds until fragrant.
Let them cool completely, then coarsely crush them using a spice grinder or mortar and pestle.
Grind the Dal: Using a food processor or high-speed blender, grind the soaked and drained dal into a thick, smooth, and airy paste. Use as little water as possible (start with 2-3 teaspoons / 15 ml / 0.5 fl oz and add more only if necessary), scraping down the sides frequently to ensure an even grind.
Combine and Rest Batter: Transfer the dal paste to a large mixing bowl.
Add the crushed toasted spices, cracked black pepper, crushed red chilies, asafetida, salt, and baking soda.
Mix gently but thoroughly. If the batter is too loose to hold its shape, stir in optional urad dal flour, one tablespoon at a time.
Cover the bowl and let the batter rest in a warm place for 4 hours.
Shape the Badis: Lightly grease a few baking sheets.
Divide the rested batter into approximately 24 equal portions.
Roll each portion into a smooth ball and gently press your thumb into the center to create a hollow indentation without piercing through.
Dry the Badis: Place the shaped badis on the prepared trays, leaving space between them.
Dry using one of these methods until they are completely hard and brittle
Sun-Drying: Place trays in direct sunlight for 2-4 days, covering with a net to protect them.
Bring indoors at night.
Dehydrator: Dry at 125°F / 52°C for 12-24 hours.
Oven: Bake at your oven's lowest temperature (around 170°F / 75°C) for 6-10 hours with the door slightly ajar, flipping halfway through.
Store and Use: Once completely cool and dry, store the badis in an airtight container at room temperature for several months. To use, crack a badi into small pieces and shallow-fry in oil until reddish-brown before adding to your dish.
When adding badis to a curry, always fry the pieces in oil until reddish-brown first. This crucial step awakens their aroma and adds a fantastic crunchy texture.