Marinate vegetables: Dice 1 potato, 1 carrot, 10 beans and 1 cup cauliflower. Mix with half cup yogurt, 1 tsp red chilli powder, half tsp turmeric, 1 tsp biryani masala and salt. Marinate 30 minutes.
Fry onions: Slice 2 large onions thinly and fry in 3 tbsp oil until golden brown. Drain on paper.
Parboil basmati rice: Wash 2 cups basmati. Soak 20 minutes. Boil in salted water with bay leaf for 7 minutes. Drain at 70% cooked.
Cook vegetable base: In a heavy pot heat 2 tbsp oil. Add 3 chopped tomatoes and cook 6 minutes. Add marinated vegetables and cook 10 minutes.
Layer: Spread the cooked vegetables as the base. Add parboiled rice on top.
Add garnishes: Add fried onions, 3 tbsp ghee and fresh mint and coriander over the rice.
Add saffron milk: Drizzle saffron milk over the rice layers.
Seal and dum cook: Cover tightly and cook on very low heat 25-30 minutes.
Rest: Rest covered 10 minutes.
Serve: Open the dum gently. Mix from the bottom. Serve veg biryani with raita and papad.