INGREDIENTS

For the mashed potatoes & fried potatoes

300 g / ⅔ pound waxy potatoes, peeled
100 g / ⅓ cup plus 2 tablespoons unsalted butter
1 tablespoon coarse Dijon mustard
Fine sea salt
Ground nutmeg
500 g / 2 cups plus 2 tablespoons vegetable oil for frying

For the fish

2 whole whitefish, scaled, gutted and cleaned
100 g / 3½ ounces hay
Fine sea salt
Herb oil, or olive oil

For the buttermilk

200 ml / ¾ cup plus 2 tablespoons buttermilk
50 g / 2 ounces sour cream
Zest of ½ lime
Fine sea salt
Ground pepper

For the Alpine milk skin

60 g / ¼ cup whole milk, preferably Alpine milk

HOW TO MAKE IT

Preparation

1. Preheat the oven to 150°C / 300°F.
2. For the mashed potatoes, boil 200 g / 7 ounces of the potatoes in salted water until soft.
3. Heat the butter over medium heat until golden brown. Drain the potatoes and transfer to the pot. Add the brown butter and mustard and mash until smooth. Season to taste with salt and nutmeg.
4. Remove the belly flaps off the whitefish and cut the fish into 4 fillets. Place half of the hay in a large, low casserole dish with a tight fitting lid, arrange the fish fillets on top of the hay and season to taste with salt. Drizzle with a little herb oil or olive oil, cover with the remaining hay and cover the casserole dish. Bake for 8–10 minutes or until the fish is just cooked through.
5. For the buttermilk, whisk together the buttermilk, sour cream and lime zest until smooth and season to taste with salt and pepper.
6. For the fried potatoes, heat the vegetable oil in a large pot until it's about 160°C / 325°F. Slice the remaining potatoes over a mandoline very thinly, rinse well and dry with paper towels. Fry the potatoes until golden brown.
7. For the Alpine milk skin, mix the milk with a pinch of salt and pour into a non-stick pan. Boil the milk over low heat until dry and crispy. Let it cool and break it into pieces.
8. Divide the mashed potatoes among the plates, place the fish fillets on top, and arrange the fried potatoes and Alpine milk skin around the fish. Drizzle with the buttermilk and serve immediately.