From memory this is. And I cheat at the campfire. Get a Dutch pot. Hang it over the campfire.
Fry off enough chunks of chicken for your hungry friends, Cook it enough to be sealed but not quite all the way through. Put aside.
Get olive oil quite a glug. Fry off onion, I tend to use half to a third of a large onion per person. And garlic, I tend to use a whole bulb whatever the population. I don't chop or crush. Nice subtle flavour this way.
When it's all nice and browned, lift higher from the fire, now is not the time for aggressive heat.
This is the cheat, a couple of major table spoons of patacks biriani paste. Dollop it in ad cook till fragrant. If you have any fresh tomatoes this is the drop them in quartered.
Right now somewhere else get your rice, basmati and seal it by frying ever so lightly. Could could do this in the dutch pot.
Now is the tense bit. Add the rice, the chicken, the onion and garlic mixture altogether. Pour in enough vegetable stock to cover everything With an inch or so of water. Squirt in tomatoe purée.
Lower and boil. Once boiling raise it up again to a v gentle bubble. Lid on don't stir, resist. Give it about 15 mins and check the bite of the rice. Don't stir.
Check again. Add more water if needed. Check until you have the right bite, but it shouldn't take too long. Just before you serve squeeze some lemon or lime. Fresh chopped coriander. Bonzer.