To prepare marshmallow mass, either a kitchen machine or a mixer should be at hand. The blender, unfortunately, does not cope with marshmallows.
For a HAND mixer, take half a serving.
So, puree: it is better to take fruits and vegetables with a high content of pectin: apple, black currant, cranberry, apricot, plum. It should be thick.
Add 180 g of sugar, heat until the sugar is completely dissolved.