Preheat the oven to 120 °C. Line a baking tray with baking paper.
Place popcorn in a blitz chopper and coarsely chop. Coarsely chop the nuts. Beat egg whites with salt until stiff. Stir in cornstarch, then stir in popcorn and nuts.
Form small balls with your hands and place on baking sheet. Place in oven for approx. 45 minutes.