Pickled herring, onions and carrots
400 g (14.11 oz) herring
100 g (3.53 oz) distilled white vinegar
200 g (7.05 oz) sugar
300 g (10.58 oz) water
6 g (0.21 oz) salt
100 g (3.53 oz) red onions
100 g (3.53 oz) carrots
10 whole black pepper corns

Crisp bread
250 g (8.82 oz) water
12 g (0.42 oz) fresh yeast
300 g (10.58 oz) rye flour
100 g (3.53 oz) wheat flour
4 g (0.14 oz) sugar
8 g (0.28 oz) salt

Instructions

Pickled herring, onions and carrots
Freeze the herring for at least 72 hours. Thaw the herring completely.
Slice the onions and carrots 2 mm thin on a mandoline.
Boil the water, sugar, salt, onions, carrots and pepper corns for 3 minutes. Let it cool.
Add the distilled white vinegar and chill to 5-8° C (46.4 degrees Fahrenheit).
If the herrings are big, slice into 2 cm bites.
Add the herring to the pickling liquid and refrigerate for 20 hours.

Crisp bread
Dissolve the yeast in the cold water.
Add the remaining Components and knead for 8 minutes.
Let the dough rise for 1 hour.
Roll the dough 1-2 mm thin.
Roll the dough with a pastry docker or use a fork to make small holes in the dough.
Cut the dough into 10 x 5 cm rectangles.
Transfer the rectangles to a baking tray lined with baking paper.
Let the rectangles sit for 10 minutes.
Preheat an oven to 180° C (356 degrees Fahrenheit). Put the bread into the oven and turn down the heat to 150° C (302 degrees Fahrenheit)
Bake the bread until crisp and golden brown.
Cool the crisp breads on a wire rack until completely cool.
Store in an airtight container until serving.

Assembly
Lightly butter the crisp breads.
Arrange the herrings, carrots and onions on each crisp bread.
Stack three crisp breads on top of each other.