This recipe takes a cue from Belyov-style pastila, which is stacked into layers, dried again, and then sliced. But Goldstein recommends simply taking two layers and sandwiching them together with jam.
6 large apples (if you’re outside Russia, Granny Smith makes a good substitution for Antonovka)
¾ cup granulated sugar
2 egg whites
Powdered sugar for dusting Source: The Historic Russian Recipe That Turns Apples Into Marshmallows – Gastro Obscura