To make the marinade, place all the ingredients into a large bowl and mix well. Add the chicken and turn several times until well coated. Cover the bowl and put in the fridge to marinate for 30 ...
Take the pan off the heat and, aiming for the space around the chicken, grate in the lemon zest, add the garlic and dried tarragon (or thyme) and give a quick stir into the oil as best you can.