- olive oil
- White wine
- Medium onion
- Peel and wash the potatoes. Slice very thinly (they will cook and before and be more crispy). Place on a baking sheet.
- Peel the onions and cut into julienne strips. Spread over the potatoes.
- Add salt and pepper and drizzle a little oil.
- Bake for 10 minutes at 200 degrees.
- After ten minutes, season the mackerel and place on top with walnut butter, a little oil, and a splash of white wine (optional). Allow 15 minutes more at 180 degrees.