Make applesauce. Place apples cut side down on a plate and microwave for 8 minutes. Scoop out the pulp with a spoon when done.
Prepare the marshmallows. Puree the cranberries using a blender and then rub through a sieve. Transfer the resulting mass to a saucepan. Add 2 tbsp. sugar. Bring to a boil over medium heat. Cook for another 5 minutes. Then cool. Combine the cranberry puree with the apple puree and egg white. Beat with a mixer until fluffy. At the same time, mix 400 g of sugar, water and agar-agar in a saucepan. Bring to a boil over medium heat. Then pour the resulting syrup in a thin stream into the cranberry-apple puree. Beat with a mixer until stable peaks form. Pipe the marshmallows onto parchment using a pastry bag. Leave it to dry for 10 hours.