Thinly slice onions and fry them in oil till golden and crisp. Set these aside half of this. If you are using store bought fried onions, you can skip this
In the same pan, add spices and saute till they begin to sizzle.
Add ginger garlic paste and fry till the raw smell goes off.
Add parboiled potatoes and the rest of vegetables. Fry for 2 to 3 minutes.
Add turmeric, masala powder and red chili powder. Mix and fry well for 2 minutes till you begin to get an aroma.
Pour 100 ml yogurt and mix. Cook till the vegetables are done to tender.
You can cover and cook. Cook uncovered if there is lot of moisture after the veggies are cooked.
While the veggies cook. Bring lot of water to a boil and cook rice till al dente along with bay leaf and shahi jeera. The rice has to be cooked grainy and not mushy. Drain it off in a colander. Soak saffron in 3 tbsps of this hot water or hot milk. Set aside.
If you like to make a 2 layer veg biryani, set aside ⅓ of the cooked vegetable mix. Now mix together the rest of the cooked veggies, rest of the yogurt, mint, coriander, nuts and raisins, few fried onions. you can do it in a pressure cooker or any heavy bottom utensil.
Making veg biryani
Layer the rice over the vegetable mix. Then layer the ⅓ cooked vegetable mix or 2 pinches of masala powder. Sprinkle some fried onions, mint and coriander.
Layer rice over it again, then the fried onions, mint and coriander leaves and pour off the saffron milk. Fry nuts in a tbsp ghee, saute raisins and then pour this over the rice. Place a moist clean cloth to seal the rim. You can even use a foil or atta to seal the utensil.
Place the dum utensil on a hot tawa and cook for 5 minutes on a medium flame and then on low for 5 to 7 minutes based on the thickness of your utensil.
Serve hyderabadi veg biryani hot or warm in layers of rice and gravy.
For the oven method:
Preheat the oven to 180 C and bake for 20 mins. if you feel it is still very moist beneath, bake for another 5 to 10 mins. This depends on what kind of baking dish you use. Usually ceramic ones get done faster.