Line a 20cm / 8in brownie tin or similar size container with baking paper

In a microwavable jug or bowl, break up the chocolate and add the condensed milk. Heat in short bursts, beating inbetween, until the chocolate is melted and the mixture is thickening.

Beat in the mint extract and the food colouring if using. Stir in most of the chopped Oreos

 Spoon the fudge into the prepared tin, then press in the remaining chopped Oreo pieces

Chill in the fridge for a couple of hours until set

Remove from the tin and chop into small squares before serving.