To make the sauce:

1. Deep fry the onions and potatoes, separately, until golden brown (the potatoes do not need to be fully cooked at this stage).
2. Set the oil aside.
3. Mix all the ingredients (except a handful of onions, to be used later) in a large saucepan, cover and simmer on a low heat for 1 hour, until the beef is tender.

For the rice:

1. Boil the washed, soaked and drained rice for 25 mins until just cooked (i.e. not mushy) and drain.
2. Take a big ovenproof dish and make alternate layers with the sauce, the rice, the sauce and finally the rice as the top layer.

For the topping:

1. Heat the oil and add all the ingredients except for the food colouring.
2. When the cumin seeds start to fry, remove from the heat and spread over the top layer of rice.
3. Sprinkle the top with the remaining fried onions (saved from earlier) and pour the yellow food colouring over the rice in the shape of a cross.
4. Cover and place in a pre-heated oven (160 deg C) for 50 mins, until the biryani has heated through.

Serving suggestions: Serve as a main course, with plain yoghurt and pickles of your choice.