320g/11oz green beans
1 leek, chopped
3 large Portobello mushrooms
200g/7oz button mushrooms, cleaned and trimmed
1 onion, chopped
30g/1oz dried porcini mushrooms, soaked in 200ml/7fl oz boiling water for 20 minutes
陆 bunch tarragon, leaves finely chopped
500g/1lb 2oz waxy potatoes, peeled
500ml/18fl oz fresh chicken stock
1 tbsp plain flour
1 bay leaf
sea salt and black pepper
2 tsp olive oil
2 skinless chicken breasts, trimmed and sliced