Wash the urad dal well. Soak it in water for 5–6 hours or overnight.

Drain the dal and grind it (without adding much water) to a smooth, fluffy paste — a texture similar to a thick batter. If using a blender, add water one tablespoon at a time.

Transfer to a large bowl and whisk or beat it by hand for 5–7 minutes. This aerates the paste — when you drop a little in water, it should float to show it’s airy enough.

Add hing, nigella seeds, and a tiny pinch of salt (optional). Mix gently.

Grease a clean plastic sheet, banana leaf, or a large plate lightly with oil.

Drop small spoonfuls (about 1 inch across) of the batter on it, keeping space between each dollop.

Place in direct sunlight for 2–3 days, turning once they’re firm enough to flip. They should become completely dry and hard.

Once dried, store the boris in an airtight jar. They keep well for several months.

When ready to eat: Heat a little oil, fry the boris until golden and crisp.

You can snack on them as is, or use them in dishes like lau bori, shak bori, or potol er dalna — they absorb the gravy beautifully!