Preheat the oven to 180c or 350f.
Mix the olive oil, lemon zest and juice, garlic, za’atar and cinnamon in a bowl large enough to fit the chicken or the poussin.
If you’re using poussin, cut them in half using a sharp knife or kitchen scissors.
Place the birds in the bowl with the marinade and leave for a few minutes while you heat the grill pan.
Once the grill pan is hot place the chicken skin side down and cook for about 10 minutes, or until there are grill marks on the chicken.
Turn the chicken over and place the pan in the oven and cook for a further 15 minutes or until the chicken is done. Chicken is cooked when it reaches an internal temperature of 74c or 165f.