Flake the smoked whitefish into small pieces, ensuring there are no bones. Finely chop the mixed olives, dill, parsley, and shallot. Rinse and chop the capers.
In a medium bowl, combine the crème fraîche and mayonnaise (optional). Stir until smooth.
Add the lemon juice, lemon zest, chopped capers, and minced shallot to the crème fraîche mixture. Mix well.
Gently fold in the flaked smoked whitefish and chopped olives. Ensure the ingredients are well combined without breaking down the fish too much.
Add the chopped dill and parsley to the mixture. Season with salt and pepper to taste, keeping in mind that the smoked fish and olives are already salty.
Cover the dip and refrigerate for at least 30 minutes to allow the flavors to meld together. Serve chilled with crackers, baguette slices, or vegetable sticks.
