In a saucepan add the chocolate chips, white chocolate chips, pastry chocolate, peanut butter and simmer over low heat for 15 to 20 minutes, stirring occasionally.
Once the ingredients are melted, remove the saucepan from the fire and let the mixture cool for 5 minutes. Add the peanuts, then drop the toffee in the slow cooker on a baking sheet covered with sulfurized paper.
Place the tray in the fridge for at least 30 minutes or until candy is set