Divide the crumbled biscuits between the glasses, drizzle with the orange liqueur. Combine the lemon curd and lemon juice, stir until smooth, spread on top.
Whisk the egg, egg yolk and sugar. Add the orange zest and orange juice, beat together in a warm bain-marie until you have a firm foam. Add the gelatine, dissolve while stirring. Stir in the orange liqueur, remove the bowl from the bain-marie, place in cold water and stir occasionally, leave to cool until the mixture is just set, stir until smooth. Beat the egg white until stiff, add the sugar, briefly continue beating. Fold into the orange crème along with the cream. Transfer the mixture to a piping bag with a serrated nozzle (approx. 8 mm in diameter) and pipe on top of the biscotti. Cover and chill for approx. 1 hr.