Mix créme fraiche with yogurt until smooth, season with salt, grated lemon zest and juice (1). Chop chervil very finely except for a few leaves, fold in.
Rinse potatoes, remove peel, grate coarsely. Remove horseradish from peel and grate finely. Finely grate fennel seeds.
Mix fennel seeds, horseradish, potatoes, egg yolks, whipping cream and flour, season with salt and season with pepper.
Bake the pancakes in hot fat in a coated frying pan until done. Serve with salmon and chervil cream. Garnish with chervil leaves and lemon slices.
Tip: The higher the fat content in the yogurt, the more aromatic and creamy the result!