Separate ladyfingers; place on large baking sheet; brush with 1 tablespoon liqueur or juice.
Sprinkle gelatin over 3/4 cup water in small saucepan; let stand 10 minutes to soften. Add 1/4 cup sugar. Heat saucepan over very low heat, stirring, until gelatin and sugar dissolve, 2 to 3 minutes. Pour into medium-size bowl. Stir in apple juice concentrate, remaining liqueur if using and egg substitute.
Place bowl in larger bowl of ice and water. Stir gelatin mixture constantly until just thickened enough to mound slightly.
Meanwhile, stand ladyfingers upright around side of 8-inch springform pan; arrange any remaining ladyfingers in bottom of pan.
Dissolve powdered egg whites in warm water in small bowl, stirring until completely dissolved. Beat until foamy. Beat in the remaining 1/4 cup sugar, 1 tablespoon at a time, until soft peaks form. Fold into apple mixture.
Without washing bowl or beaters, beat cream until soft peaks form. Fold into apple mixture. Pour into prepared pan. Refrigerate at least 4 hours, or until set.
To serve, run knife around edge of pan. Remove side of pan. Place charlotte on serving plate. Garnish with whipped cream if desired.