40 g butter (30 g for the stuffing and 10 g to finish)
2 or 3 beetroot in a range of colours
300 ml fish fumet
100 ml crème fraîche Isigny
Salt, white pepper
Dry white wine Riesling Hunawihr
Finely grate the Crémeux des Alpes. Set one half aside and put the remainder in a large bowl. Add mushrooms, diced butter and chopped dill. Mix well.
Slice lemon thinly, cut each slice in half and set aside.
Wash mackerel and cut lengthwise. Put 2 lemon slices in each opening, then stuff with the mushroom and cheese mixture. Season with salt and pepper before closing the fish with a toothpick, ensuring that no stuffing escapes. Flour the mackerel and lightly brown each side in olive oil.
Peel the beetroot and slice thinly. Fry lightly in olive oil so that they retain their colour. Sprinkle with salt, pepper, herbs and a little cumin then leave to macerate for a few minutes. Next moisten with a little white wine.
In a frying pan, sweat the onions and garlic in olive oil. Deglaze with a little white wine and simmer for a few minutes. Now add the fish fumet, stir in the remaining Crémeux des Alpes and allow to thicken. Add a drizzle of crème fraîche, salt and pepper.
Froth the sauce with a stick blender (optional).
Brush the mackerel with a little melted butter to make the skin nice and shiny before serving.
The stuffing can be adjusted to suit your taste. For example, you might opt for a stuffing made with spinach seasoned with nutmeg and cumin Albert Ménès.