In a mixing bowl, add 1 cup small-grain rice, ½ cup chana dal, ¼ cup toor dal, ¼ cup urad dal, 1 tsp methi seeds, and ½ cup poha. Wash everything thoroughly. Add 3 cups of buttermilk and soak the rice and dals for 5 hours.
Transfer the soaked rice-dal mixture along with the buttermilk to a mixer jar and grind it into a smooth batter. If needed, add a little water while grinding.
Transfer the ground batter to a mixing bowl. Add salt to taste, ½ tsp turmeric powder, 1 tsp red chilli powder, ½ tsp black pepper powder, 1 tsp sugar, 2 tbsp green chilli-ginger-garlic paste, 2 tbsp crushed peanuts, 2 cups grated lauki (bottle gourd), and ½ cup chopped coriander leaves. Mix well.
Heat 3 tbsp oil in a tadka pan. Add ½ tsp mustard seeds, ½ tsp cumin seeds, 1 tbsp sesame seeds, 5–6 curry leaves, a pinch of hing, and 2 dry red chillies. Prepare the tempering and add it to the batter. Mix well.
The handvo batter is now ready. Divide it into two equal portions.
Add 1 tsp Eno fruit salt and 1 tsp lemon juice to one portion of the batter. Mix gently until the batter becomes light and frothy.
Heat a kadai and grease it with a little oil. Sprinkle some sesame seeds and curry leaves at the bottom.
Pour the prepared batter into the center of the kadai. Cover and cook on a low-medium flame for 12–15 minutes.
Carefully flip the handvo and cook the other side for 5–7 minutes, or until it becomes golden brown and crispy from both sides.
Similarly, prepare the remaining handvo in a small tadka pan.
Cut the handvo into the desired shape and serve hot with green chutney.