To blanch the potatoes:
Place a large bowl of ice-cold water on the kitchen counter. Add the potatoes to a pan of water then bring the water to a boil. Reduce heat to a fast simmer, checking potatoes periodically. Cook for around 8 minutes until soft and check with a knife. Remove from heat, drain and plunge potatoes into the bowl water. Leave potatoes until cool to touch and slice.
To make the gratin:
Pre-heat oven to 200C/180C fan/gas 6.
Rub the inside of a gratin dish with garlic then layer with the sliced potato then a layer of fish and spinach, season and sprinkle over a pinch of nutmeg, pepper and chives. Season each layer as you go until you reach the top of the dish, finishing with a layer of potato.
Pour the cream, butter and garlic clove into a saucepan, season a little, bring to just under the boil then turn off the heat. Remove the garlic clove then pour over the gratin.
Cover the top with the parmesan and chives and bake for 20 minutes until golden.
600g Rooster Potatoes, peeled and thinly sliced
400g smoked haddock, cut into pieces
350ml ½ fat cream
A handful of spinach
2tbsp chopped chives
1tsp grated nutmeg
1tbsp grated Parmesan
A clove of garlic, peeled
Salt and pepper