Make applesauce. Cut apples into cubes, put in a saucepan, pour in 100 ml of water, bring to a boil, cook for 5 minutes, drain the water. Transfer the boiled apples to a blender, grind into a puree. Transfer the puree to a saucepan, add sugar, stir, bring to a boil. Remove the puree from the heat, let cool and put in the refrigerator for 7-10 minutes. While the puree is cooling, separate the yolk from the white. Remove the puree from the refrigerator. Beat the white with the applesauce until fluffy.
Prepare the syrup. Combine agar-agar, 60 ml of water and sugar in a saucepan with a thick bottom. Put on the fire. Stirring constantly, bring the mixture to a boil and simmer until the syrup thickens.
Prepare the marshmallow mass. Pour the syrup into the apple-protein foam in a thin stream and beat with a mixer at maximum power. Transfer the finished mass into a pastry bag. Cover the baking sheet with parchment. Place the marshmallow on the baking sheet. Leave the marshmallow on the table to dry for 6 hours. Sprinkle the dessert with powdered sugar and leave on the table for another hour. Separate the halves from the parchment and connect two pieces together.