1 tsp horseradish sauce
1 tsp finely chopped shallot
1 tbsp tomato ketchup
1 tbsp mayonnaise
2 cornichon or ½ dill pickle, finely chopped
dill pickles, to serve
dash Worcestershire sauce
salt and freshly ground black pepper
pinch hot paprika
butter, for spreading
few slices Swiss cheese, such as emmental or gruyère
2–3 slices salt beef
2 slices light rye bread or sourdough
2–3 tbsp sauerkraut