Pat the wild salmon fillets dry. Finely chop the onion and garlic and wash the leaf spinach thoroughly.
Gently heat olive oil in a frying pan and cook the onion and garlic until soft and translucent. Add the leaf spinach and let it wilt briefly.
Stir the cashew butter with a little water and the lemon juice until smooth. Season with nutmeg and salt and fold into the spinach.
Put the spinach mixture in a baking dish and place the wild salmon fillets on top. Season with pepper and cook in the oven at 200 °C (180 °C fan) for 12–15 min until the salmon is just cooked through and still juicy.
Leave the gratin to rest briefly. Finish with a little lemon juice if you like.
Serve hot, ideally straight from the dish.
Good to know
An oven dish that feels light but is still satisfying. The salmon stays juicy, the spinach turns creamy, and everything ends up in one dish without much effort.
Swaps
Wild salmon → Arctic char (also plenty of protein, with omega-3 fatty acids); cashew butter → almond butter (more vitamin E, a little stronger in flavour); leaf spinach → chard (similar minerals, a little more bitter); olive oil → ghee (heat-stable and full-flavoured).
Allergens
Contains fish and cashews (tree nuts). Season mildly for children and watch out for bones; during pregnancy, cook it through well and only use fresh, properly chilled fish.