1.Lightly grease and line a 18X28cm slice pan with baking paper.
2.In a medium bowl, mix biscuit crumbs and butter. Stir until combined. Press firmly into base of pan. Chill.
3.Meanwhile, in a medium saucepan, stir condensed milk, extra butter, syrup and sugar on low, for 12-15 minutes until caramel in colour. Pour over biscuit base. Chill for 1 hour until set.
4.In a medium heat-resistant bowl, combine chocolate and oil. Place over a saucepan of simmering water. Heat, stirring, for 4-5 minutes until smooth.
5.Reserve 1/3 cup crushed Oreos. Gently fold remaining through chocolate. Spread over caramel and sprinkle with extra Oreos. Chill for 1 hour or until set. Cut into squares. Store in an airtight container in the fridge.
Use any favourite chocolate biscuit in place of oreos.Note