Stir the quark with the powdered sugar. Gradually add the yogurt to the quark. Soak the gelatine in cold water for about 5 minutes. Squeeze the gelatine well. In a saucepan, heat the orange juice and the juice of one lemon. Let gelatine melt in it. Stir the gelatine-juice mixture into the quark-yogurt mixture and let it set. Whip cold cream in a cold baking bowl until stiff. Fold the cream into the quark and yogurt mixture. Line a baking dish with cling film and pour in the mixture. Place in the refrigerator for one night.
Spread the strawberries through a sieve. Mix the strawberry puree with the remaining ingredients and whisk to a creamy consistency. Cut kiwi, strawberries and banana into slices. Turn out the yogurt-quark terrine and cut into 3 cm wide slices. Arrange the yogurt-quark terrine with the fruit and the mint leaves on plates. Add the strawberry sauce, drip a few drops of yogurt onto the sauce with a teaspoon and shape it into a heart shape with a toothpick.
Tip: The higher the fat content in the yogurt, the more aromatic and creamy the result!