1.Grease a 20cm x 30cm (8-inch x 12-inch) rectangular cake pan, line base and sides with baking paper, extending paper 5cm (2-inches) above sides.
2.Place ice-cream in a large bowl. Gently fold in Smarties. Spoon mixture into pan, smooth surface. Freeze for 2 hours or overnight until firm.
3.Preheat oven to 180°C (160°C fan forced). Grease and line oven trays with baking paper.
4.Cut cookie dough into 16 x 1cm (½-inch) thick slices, place 2cm (¾-inch) apart on trays. Bake for 10 minutes or until golden brown. Cool on trays.
5.Cut eight rounds from ice-cream using round cutter, sandwich each round between 2 cookies. Place on a tray, freeze for 30 minutes or overnight until firm.
For variety you could use strawberry or chocolate flavoured ice-cream instead of the vanilla. Make this cake the day before the party to allow the ice-cream sandwiches time to firm up.Note