Add the chocolate melts and tin of condensed milk into the slow cooker
Stir with a metal spoon every 10 minutes, cooking on high for 1hr
When a smooth even mixture is formed, add green food dye to desired shade
Add peppermint essence a few drops at a time and stir through
Pour into lined baking dish
Whilst the mixture is still warm, add a few drops of food dye and swirl with a toothpick
Place in fridge to set and then cut into desired shapes