Curry sauce for herring

One of the most classical & widespread ways of serving herring in Denmark is with curry sauce, and it appears this will be the last variety of herring I make this winter. In Denmark this can be bought, either as a side or as herring pieces in curry sauce. Whichever way you prefer it, it can be quite delicious if you make your own fresh curry sauce - and being far from Denmark I found I had little choice.

Ingredients:
- 2 tbsp mayonnaise
- 2 tbsp sour cream
- salt & pepper
- 1 tsp hot madras curry powder [1]
- 1/3 small onion
- 1 hard-boiled egg
- 8 cornichons

The onion, egg, and cornichons were chopped medium finely and everything was stirred together.

Served with pieces of pickled herring on dark whole grain rye bread.

[1] My hot madras curry powder lists the following ingredients: fenugreek, coriander, cumin, turmeric, red pepper - but states the list isn't complete.