salt
freshly ground black pepper
4 higher-welfare spring chickens or poussins
1 small handful fresh parsley , leaves picked, stalks kept
1 bunch fresh tarragon , leaves picked, stalks kept
4 teaspoons wholegrain mustard
2 heaped tablespoons plain white flour
extra virgin olive oil
1 white onion , peeled and finely chopped
2 cloves garlic , peeled and finely sliced
½ heart celery , trimmed back and finely sliced
2 good knobs butter
2 wineglasses crisp white wine
565 ml organic stock
3 gem lettuces , quartered
1 small bunch seedless grapes , washed and halved