Chop the Harz cheese quite finely and add the onions.
Mix together the butter, mustard, paprika, egg yolk and cream and stir in. Let everything sit for a few minutes.
Place the fresh farmer`s bread slices on plates or boards and cover with the washed lettuce leaves. Spread the cheese salad on top and cover with tomato slices. Finally, garnish with creme fraiche and chives rolls or chopped wild garlic or possibly both.