Peel and thinly slice 8 medium potatoesPlace in a pot on the stove top (with a pinch of salt) and bring to the boil.Thinly slice one large onion.Grease a casserole dish and layer the potato and onion, season each layer.Pour 300ml of cream over the combined potato and onion.Cover and bake in an oven at 180 degrees for one hour.Remove the lid and bake for a further 30 minutes.