Mix the cornstarch with 2-3 tablespoons of cherry juice (from the glass) until smooth.
Heat the cherries in a saucepan, stir in the cornstarch mixture until smooth, stir in the liqueur and allow to cool.
Whip the cream. Mix the yoghurt, sugar and sour cream, fold in the whipped cream. Pour sour cream and cherries in layers into (transparent) glass bowls with a tablespoon and decorate each with an amarena cherry. Refrigerate.
Annotation:
The dessert looks best when you start filling the glass bowl with the cherries and finish with the cream.