How to Make Bonfire (Treacle) Toffee Makes 1¼lb toffee 1lb dark brown sugar ¼ pint water ¼ level tsp cream of tartar ½ cup black treacle/molasses ½ cup corn syrup Preparation: I just sprayed pie tins with Pam. In a heavy based 4-pint stainless steel sauce pan dissolve sugar and water over a low heat. Once dissolved, add all the remaining ingredients, turn up the heat and bring to the boil. Using a sugar or toffee thermometer boil to 270°F (soft crack). Then pour into pan(s).