1Combine the tomato paste, half of the olive oil, paprika, chilli powder and lemon juice in a large bowl, mix well, and toss the chicken in the marinade to coat completely.
2Heat the remaining oil in a large heavy-based frying pan over medium heat and sear the chicken skin-side down until the skin renders and browns, about 6-8 minutes, then remove to a tray.
3Dice the red onion and carrot, add them to the pan and cook for 3 minutes until softened.
4Deglaze the pan with a little of the stock, add the cinnamon stick, cumin, and salt, then cook for 2 minutes.
5Drain the rinsed rice, add it to the pan with the vegetables, then stir in the remaining stock and return the chicken to the pan.
6Bring to a simmer, reduce the heat to very low, cover with a lid and cook for 15 minutes.
7Remove the chicken to a tray, discard the cinnamon stick, stir the rice, add the spinach, cover, and let sit off the heat for 2 minutes before serving.