600g/1lb 5oz green beans
16 baby leeks
4 tsp finely chopped fresh flatleaf parsley
2 banana shallots, finely chopped
2 tsp finely chopped fresh tarragon
陆 tsp Dijon mustard
salt and freshly ground black pepper
100ml/3陆fl oz olive oil, plus 1 tbsp olive oil for frying
2 tbsp cider vinegar
4 large chicken breasts, skin on