For the base, place the crushed digestive biscuits into a bowl with the ginger and melted butter and mix well.
Place a 25cm/10in chefs' ring onto a large plate and press the digestive biscuit mixture into the base.
For the filling, place the condensed milk, double cream and lime juice into a bowl and whisk together until thick.
Pour the filling mixture onto the base. Place the pie into the freezer for ten minutes to set.
To serve, carefully remove the chefs' ring and drizzle the melted chocolate over the pie. Garnish with lemon wedges.