Stir the quark until smooth. Season to taste with a few drops of sweetener. Roast the hazelnut leaves in a pan without fat until golden brown, remove. Peel and slice the banana. Spread crispbread with quark and cover with banana slices.
Sprinkle with hazelnut leaves and sprinkle each with a teaspoon of maple syrup. If desired, decorate with mint and physalis.