Herring in sour cream with apple (Śledź w śmietanie)

1. If the herring fillets are very salty, soak them in cold water (or milk) for 1-2 hours, changing the water once; then pat dry with kitchen paper.

2. Cut the fillets diagonally into 2-3 cm pieces.

3. Slice the onion into thin half-rings, pour boiling water over it and drain – it loses its sharpness but stays crisp.

4. Peel, core and dice the apple; dice the pickled cucumbers too. Sprinkle the apple with a little lemon juice straight away so it doesn't brown.

5. Mix the sour cream with the onion, apple, cucumber and most of the dill, season with pepper, then gently fold in the herring; chill for at least 1 hour so the flavours come together.

6. Serve sprinkled with fresh dill, with boiled new potatoes or rye bread.

Tip: A must-have cold starter on the Polish Christmas Eve table; the tart apple and creamy sour cream balance the saltiness of the herring beautifully.