- 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.
😉 Tip: 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.