Crush the Oreos in a food processor or with a rolling pin until they are fine crumbs.

Mix the crumbs with melted butter until well combined.

Press this mixture into the bottom of a springform pan or a lined cake tin to form the crust. Chill in the freezer for about 10 minutes.

Spread the softened vanilla ice cream over the chilled crust, smoothing it out evenly.

If you wish, you can mix in some crushed Oreos into the ice cream for an extra layer of texture.

Cover the cake with plastic wrap and freeze for at least 4 hours, or until the ice cream is firm.

Once set, remove from the freezer, and if using, decorate with whipped cream and more crushed Oreos or drizzle with chocolate syrup.