In a bowl, mix together graham cracker crumbs, melted butter, sugar, and vanilla extract. Press the mixture into the bottom of a 9-inch springform pan.
Spread the softened vanilla ice cream over the crust layer and smooth the top.
Freeze the first layer for 1-2 hours or until firm.
Layer the softened orange sherbet over the firm vanilla ice cream and smooth the top.
Freeze again for 2-3 hours or until completely firm.
Before serving, remove the cake from the springform pan and garnish with whipped cream.
Notes
Ensure each layer is completely frozen before adding the next.