A classic Swedish Herring sandwich works to serve as a starter always. At least in Sweden. So you use some ready made herring. Or pickle it yourself according to my recipe in another post.
Pickled herring 125 gram, normally it weighs 200 grams with the brine . Cut into small pieces.
2-3 Eggs, hard boiled, in small pieces
1 Apple, in small pieces
Dill, just a little
Mayonnaise, 1/2 decilitre
Half a red onion or a leek chopped in small pieces
Mix it all in a bowl.
Then add it on a piece of dark bread with some salad.
You can add other thing of course, mango is nice for example. And walnuts !