1. Soak the chana dal and rice in a bowl of water for 4-6 hours or overnight. Grind this to a fine paste and remove into a large bowl. Mix in the oat and ragi flour, chopped drumstick leaves, green chilies and salt. Whisk to combine.
2. Heat a non-stick pan or cast iron skillet. Smear with some oil using kitchen paper.
3. Pour tablespoonfuls of batter around the tava (3-5 at a time depending on tava size). Drizzle some oil around the edges of all the adais.
4. Cook over medium flame for 2-3 minutes per side until cooked and golden brown. Serve hot with any chutney of choice.