Wipe the chicken thighs with kitchen paper. Finely grate the zest from 1 lemon and squeeze the juice from both.
Mix in a shallow dish with the tarragon, 1 tbsp of the oil, and some salt and pepper. Slash the skin of each chicken thigh three times, then turn in the marinade. The chicken pieces can be cooked immediately or left in the fridge for up to a day.
Cut the potatoes into wedges and spread over a roasting tin. Toss in the remaining oil and sprinkle with paprika. Set a rack on top and arrange the chicken pieces on the rack.
Bake for 30-40 mins, until the chicken is well browned and the potatoes tender.
