Drain tuna well. Peel and chop the onion. Puree tuna and onion together. Stir in mayonnaise and yoghurt. Add capers.
Season to taste with salt and pepper. Puree smoked trout fillets and cream cheese. Stir in crème fraiche. Season with salt and pepper. Clean and wash the mushrooms and unscrew the stems. Fill the mushrooms with the trout cream. Garnish with trout caviar and parsley leaf. Halve, clean and wash the peppers. Fill one half each with the tuna cream and garnish with parsley. Cut the remaining peppers into strips.
Garnish with trout caviar and parsley leaf. Halve, clean and wash the peppers. Fill one half each with the tuna cream and garnish with parsley. Cut the remaining peppers into strips. Clean or peel and wash the celery, cucumber and carrots. Cut the vegetables into sticks as well. Arrange on a plate with the stuffed vegetables