For this, I used a large, cast-iron Dutch oven or casserole pot that was big enough to hold all the chicken pieces in a single layer.
Add the butter and olive oil to the pot and set it on a medium-high heat. As soon as the buttery oil starts to foam, add the chicken thighs, skin-side up. Drop the heat to low-medium and let the chicken fry for 5 minutes. Then turn the pieces over and let them fry for another 5 minutes. With that gentle frying, you’re looking to get a light golden color — and I mean light golden — on each side. Remove the thighs with a slotted spoon and set them aside on a plate — and try to leave as much buttery oil as you can in the pot.
Repeat the same frying process with the drumsticks. You’ll need to turn these a few times as they slowly fry in order to give them a fairly even, pale gold color all over. That’ll take about 10 minutes on that low-medium heat. Remove the drumsticks with a slotted spoon, and set them on the plate with the thighs.
Turn the heat to medium, and stir all the dersa into the buttery oil. Give it a few stirs, and as soon as it starts to bubble, pour in the water, and give the whole lot a good stir. Let the mix come up to a bare boil and drop the heat to low. Now lay all the chicken pieces into the pot in a single layer. You don’t need to stir the pieces onto the dersa sauce, just lay them down in it. Cover the top of the pot with silver foil and put the lid on. You’re aiming here to create a good seal with the foil and the lid. You now want to let the pot cook at a very slow simmer on that low heat for 40 minutes.
When that 40 minutes is up, uncover the pot and add the chickpeas. Use a wooden spoon to work the chickpeas gently between the chicken pieces and into the dersa sauce. Take some care here so as not to break up the chickpeas or to separate the skin from the chicken. You’ll probably find that not all the chickpeas will be immersed in the sauce — that’s fine. Also, the chicken won’t be covered by the sauce either — that’s also fine. Now cover the pot again with the foil and the lid, and let it simmer away on low for another 10 minutes. Done. Turn off the heat and let the pot sit while you sort out the zucchini, peppers, and the couscous.