Preheat oven to 170°C (350°F). Place the butter, caster sugar, brown sugar and vanilla in an electric mixer and beat for 2 minutes. Add the eggs, one at a time, beating well after each addition until ...
you'll want to get it in the fridge so the cookies will soften and the cake will set. This is the "icebox" part of the icebox cake. Make sure you refrigerate it at least six hours, or overnight.