Prepare the apples. Place the apples on a baking sheet and bake for 30 minutes at 180 degrees. Remove from the oven and let cool. Beat the apples with a blender, rub through a sieve to avoid lumps.
Soak gelatin in 30 ml of water.
Cook the syrup. Dissolve sugar in 50 ml of water. Bring to a boil, cook for 5-6 minutes, stirring.
Make the marshmallow mass. Beat the applesauce with the egg white at medium speed with a mixer. Add the diluted gelatin and vanilla. Mix with a mixer for 1 minute. Pour the sugar syrup into the mass, beat for 10-15 minutes. Transfer the mass into a pastry bag, place the marshmallow on a baking sheet with parchment or a silicone mat. Put the marshmallow in the refrigerator for 3 hours.