1kg of floury potatoes, sliced very thinly
200ml of double cream
200ml whole milk (I used semi-skimmed)
1 clove of garlic halved
140g of smoked salmon cut into bite sized pieces
50g Grand Padano (parmesan would be fine)
Heat the oven to 160ºC. Gently heat the cream and milk with the halved garlic clove. Season really well, then turn off the heat and leave for 10 minutes. Take out the garlic and discard. Stir in the salmon.
Put the spinach in a colander and pour over a kettleful of water to wilt. Cool then tip into a clean tea towel and squeeze out as much water as possible (or else it will dilute the gratin). Season and add a grating of nutmeg.
Butter an ovenproof dish. Layer the potatoes and spinach, spooning over salmon and cream as you go. Finish with a layer of potatoes and squash down so the cream just comes to the surface. scatter with the cheese. Cover with foil and bake for 1½ hours , removing the foil after 45 minutes.
Make a healthier version by using half fat creme fraiche in the place of double cream.