Pour milk into a small metal bowl; place mixer beaters in the bowl. Cover and refrigerate for at least 2 hours or overnight. Line the sides of a 9-in. springform pan with ladyfingers; set aside.
In a large bowl, dissolve gelatin in orange juice. Stir in the sugar, lemon juice and zest; cool to room temperature.
Beat chilled milk until soft peaks form; fold into gelatin mixture. Pour into prepared pan. Refrigerate for at least 3 hours or until firm. Spread with whipped topping. Remove sides of pan. Refrigerate leftovers.