Add the sumac, salt, black pepper, sour cream and the juice of ½ a lemon into a bowl and mix together until combined.
Next up, we will be extracting the juice from the onion. Start by finely dicing the onion with a knife, food processor or cheese grater. The point here is to chop the onion as finely as possible.
Once the onion has been processed, we can use a sieve or muslin cloth or separate the juice from the pulp.
Once all the juice has been separated, stir it into the marinade mixture and set aside.
Now, in a mortar and pestle, grind the saffron. Once the saffron has been ground, add a small drop of hot water to the saffron. This is called “blooming”. Stir the saffron liquid around for 15 seconds, then add to the marinade mixture we just created. At this stage, the marinade has been prepared.
Now, cut the chicken into cubes, and mix together with the marinade.
Cover the bowl with plastic wrap and let the chicken marinate on your kitchen counter top for 1 hour at room temperature.
After one hour, preheat your oven to 390°F (200°C).
Take your chicken and lay the pieces out on parchment paper on an oven rack/tray.
Place in the oven and let the chicken cook for 10 minutes or until 60% done.
Once the chicken has been 60% complete, take the partially cooked chicken out of the oven. We are not finished cooking the chicken yet.
Heat a large frying pan to a medium-hot temperature and toss in a generous knob of butter.
Now place the partially cooked chicken onto the frying pan and cook for another 10 minutes until the centre of the chicken 100% cooked and white. It's very important that you cook the chicken thoroughly. (This two-step process creates a bbq grill style of flavour, but it is very important that you make sure the chicken has been thoroughly cooked. If in doubt, just leave it in the oven as you normally would).
Take your chicken off the pan and garnish with chopped cilantro and a squeeze of a lime.