Freeze lemon juice in cubes. Boil water and sugar until syrupy, then cool. Blend frozen lemon juice with syrup until creamy.
Coat lemon slices in powdered sugar, lay on silicone mat, and dry for 2–3 days or dehydrate at 120°F for 3 hours.
Mix sugar and egg whites, then stir in flour. Spoon mixture into rounds on silicone mat and bake at 350°F for 10–12 minutes. Shape into cups while warm.
Scoop lemon sorbet into cooled cookie cups and garnish with lemon chips before serving.
