Make applesauce. Bake apple halves with skin in the microwave for 10 minutes until soft. Scoop out the pulp and transfer it to a blender bowl. Make applesauce. Add 100 g fructose and vanillin. Stir and let sit for 1 hour.
Soak agar-agar in cold water. Put on the fire, add 200 g of fructose, stir, bring to a boil. Cook the syrup for 5 minutes on moderate heat. Turn off the heat, let it cool a little.
Prepare the marshmallow mass. Add the egg white to the cooled apple puree and beat with a mixer at medium speed. Slowly pour the syrup into the mixture and continue beating for 10-15 minutes until fluffy and stable foam forms.
Form the marshmallow halves. Transfer the mixture into a pastry bag. Line a tray with baking paper. Pipe out the marshmallows in portions and let them dry on the table for 12 hours. Assemble the marshmallows from the two halves. They stick together well.