Line a rimmed baking tray with cling-film and place in the freezer. Using a ¼ cup ice-cream scoop, make a rounded ball of ice cream. Press your thumb into the centre to make an indentation, and fill it with a Malteser, then press the ice cream over and seal, then transfer the ball to the baking sheet in the freezer. Repeat to make 18 ice cream balls and freeze until hardened (about 2/3 hours).
Remove the ice cream balls from the freezer and allow to soften at room temperature for 3 to 5 minutes (this will help the crushed wafers and chocolate chips stick).
Put crushed wafers and chocolate chips in a shallow dish, roll ice cream balls into the mixture, and pat to coat. Place tartufo on a baking sheet, and freeze for at least 2 hours before serving.