Soak rice in water and set aside for 15-20 min.
Heat oil in a large heavy bottom pot on medium to high heat. Add onions and saute them until caramelize (for about 8-10 min).
Put black cumin, minced garlic, green chili and cook for about 1 min
Add cauliflower, carrots and french beans and saute for 6-8 min
Finally add yogurt, lemon juice, green peas and soaked rice: gently mix well.
Season the mixture with salt and biryani masala.
Add water or vegetable stock and bring mixture to boil.
Then add freshly chopped mint and cilantro and simmer the biryani mixture on low heat for about 18-20 min.
Serve warm to enjoy this flavorful veg biryani.