Instructions

1. Peel the marrow and cut it in half vertically. Scrape out the seeds then shred or grate roughly the flesh into a colander. Scatter a Tbsp of slat, mix well - then let it rest for 15-20 minutes.
2. In the meantime, finely chop the onion. Heat the oil in a saucepan and gently cook the onion until soft. Add half of the dill, and stir for a minute.
3. Squeeze the excess liquid out of the marrow and add to the onion.
4. Add enough stock to cover the marrow, then the bay leaf. Cover and simmer for about 15 minutes – add more stock, if necessary.
5. When the marrow is soft, add the sour cream or yoghurt (mixed with cornflour, if preferred), then cook until the sauce thickens.
6. Season with ground pepper and add the remaining dill. Add the vinegar or lemon juice, taste, and adjust it to your liking.