For the chicken, preheat the oven to 180C/160C Fan/Gas 4.
Sprinkle the flour onto a plate and season with salt and pepper, then dredge the chicken pieces in the flour.
Heat half of the oil in a large frying pan over a medium heat. Fry the chicken in batches for 2-3 minutes on each side, or until golden-brown on both sides. Remove from the pan using a slotted spoon and transfer to an ovenproof casserole.
Heat the remaining oil in the same pan, then fry the onions, garlic and peppers for 4-5 minutes, or until just softened. Stir in the tomato purée and continue to fry for 1-2 minutes, then pour in the sherry and white wine and bring the mixture to the boil. Stir in the tinned tomatoes, espelette pepper and sugar and return to the boil. Season with salt and pepper.
Pour the sauce over the chicken pieces. Cover and bake for 1-1½ hours, or until the chicken is cooked through and no trace of pink remains, the peppers are tender and the sauce has thickened slightly.
Meanwhile, for the pilau rice, heat the oil in a large lidded frying pan over a medium heat. Add the onion and fry for 2-3 minutes, or until softened but not browned. Add the cloves and cinnamon and cook for another 1-2 minutes, until fragrant. Add the rice and stir well to coat it in the oil, then pour over 600ml/20fl oz water and stir again.
Add the bay leaves and 2 lemon slices, then cover the pan with a lid and reduce the heat until it is just simmering. Cook the rice for 15-20 minutes, or until it is just tender and all the liquid has been absorbed. Remove the lemon slices and bay leaves before serving.
To serve, stir the parsley into the chicken and season again. Serve with the pilau rice. Garnish the plates with the remaining lemon slices.