Rinse the tomatoes, cut into quarters and cook in butter until creamy. Extinguish with vinegar, add tarragon and spices. Briefly simmer lightly.
Stir the pre-soaked gelatine into the tomato mixture. Puree, pass through a sieve and cool.
Fold in the whipped cream as soon as the gelatin sets. Cool for 3-4 hours.
For the sauce, stir together crème fraîche and yogurt. Stir in tarragon and season to taste.
Dress the cress in a dressing of tarragon vinegar, oil, salt and pepper. Portion the tomato mousse and serve with cress, dressing and egg halves.
Tip: Cook only with high-quality spices – they are the be-all and end-all in a good dish!