1. Spatchcock each poussin by cutting it along the backbone with a knife or scissors. Flatten them with the palm of your hand, then rub with the grated garlic and season generously all over with salt and the cayenne pepper.
2. Heat the butter and oil in a large, heavy-bottomed frying pan. Cook the poussins, cut side down, over medium heat for 3 minutes, then flip them over and cook them, skin side down, for 5 minutes.
3. Lower the heat and place a cartouche (a circle of baking parchment or wax paper) over the birds, followed by a smaller frying pan on top. Weight it all down with something heavy.
4. Cook for 20–25 minutes over the lowest possible heat. To test that the poussins are cooked, pull away at the legs –- they should come away easily and the juices should run clear.
5. When the birds are done, lift them out and let rest on a chopping board for 5 minutes. Add the herbs to the buttery juices in the pan and cook for another minute or two.
6. Serve the poussins drizzled with the herby juices, or mop the juices up with some good bread, along with the Tkhemali.