Wash the potatoes well and precook them about 20 minutes.
Season chicken breasts with salt and pepper and grill them, then cut into strips.
Cut spring onions into rings. Cut a lid from the potatoes,  and hollow out. Fill potatoes with onion rings and chicken breast strips. Cover each potatoe with one slice herb butter.
Wrap potatoes in aluminum foil and grill for 10-15 minutes.