Preheat oven to 180°C (350°F). Grease a baking dish.
Soak ½ cup rice and ½ cup chana dal (split chickpeas) for 4–5 hours or overnight. Grind into a smooth batter.
Add ½ cup yogurt, 1 tsp ginger paste, 2–3 green chilies (chopped), salt, ½ tsp turmeric, and 1 tsp baking soda. Mix well.
Fold in 1 cup grated bottle gourd (or zucchini) and optional chopped vegetables like carrots or peas.
Pour batter into the greased baking dish and smooth the surface.
Bake for 35–40 minutes until golden brown and a skewer inserted comes out clean.
Temper with mustard seeds, curry leaves, and green chilies in ghee or oil; pour over the baked handvo.
Serve warm with chutney or yogurt.