Skin the trout and pluck the bones with a small knife. Peel and chop the shallot.
Puree the trout and shallots in a blender, add the creme fraîche and gradually add enough cream to make a smooth cream. Season with salt and white pepper (from the mill). Cool well.
It tastes great on round pumpernickel slices or crackers sprinkled with the finely chopped dill.