Wash the blueberries, put some nice fruits aside for decoration. Coarsely chop the mint leaves.
Put the berries and mint together with the skyr in a blender jar and mix, season with powdered sugar and the juice of half a lime. Then stir in the instant gelatine.
Place crumbled amarettini in dessert glasses, pour the mousse on top, cover and place in the refrigerator overnight. Decorate the next day with amarettini and blueberries.