For this recipe, you could use Greenlandic pilchuck prawns, for example.
Make sure you have enough prawns (approx. 80 g per smørrebrød). Start by removing the head from the prawn. Then hold the tail firmly whilst gently opening the side shells and removing the shell from the upper body. Finally, continue to hold the tail, squeeze it gently, and pry the prawn free from the tail.
Whisk together the mayonnaise, crème fraîche, ketchup, balsamic vinegar and Worcestershire sauce in a bowl. Grate the horseradish as finely as you can and crush the garlic. Now season the sauce with horseradish, garlic, cayenne pepper and paprika – you may not need to use it all. The sauce should be tangy, sweet and warming, but not overwhelmingly hot. Adjust with salt and, if necessary, pepper. Add a touch of freshness with lemon juice and, if desired, more ketchup.
Onions:
Start by peeling the onions and cutting them into 2 cm wide wedges lengthways, following the grain of the onion. Toss the onions thoroughly with salt in a bowl and leave them to stand for about 1 hour. Place the onions in a sieve, rinse them briefly, then transfer them to a sterilised preserving jar.
Preserving liquid:
Place all the ingredients for the preserving liquid in a saucepan and bring to the boil until the honey has completely dissolved. Allow the liquid to cool, then pour it over the onions. The onions will keep for about a week in the fridge.
Toast slices of sourdough bread in a generous amount of butter and a dash of olive oil until golden on both sides. Place small dollops of spiced mayonnaise on the bread, then arrange the prawns on top. Grind a little fresh pepper over the whole dish and add several small dots of mayonnaise around the bread. Finally, top with pickled salad onions and fresh herbs. Serve on a plate, perhaps with a little lemon on the side.
