Leave the potatoes to soak in cold water for 10 minutes to reduce the starch. Wash the spinach and wilt briefly in a little hot butter. Allow to cool and roughly chop.
Season the onion, tomato and courgette slices. Layer in a gratin dish with the well-dried potatoes and spinach, seasoning as you go. Put some fresh parsley into the cream and pour over the vegetables. Cook in any way that