Layer a large baking tray or cookie sheet with 1 layer of tin foil and 1 layer of baking paper. Cover evenly with the plain crackers at set aside.
Make the caramel sauce by heating a saucepan with the water and sugar until it begins to boil. Ensure you stir the mixture constantly. Add the sea salt and coconut oil (or butter) and continue stirring on medium heat until it thickens and remove from the heat.
Pour the caramel sauce over the crackers until they are all evenly covered. Grind course sea salt over it and set aside.
Make the dark chocolate by heating the coconut oil in the saucepan until melted. Add the vanilla essence and slowly sift in the cocoa powder and stir very well until fully incorporated.
Pour the chocolate sauce over the crackers and caramel sauce evenly and add more salt. Refrigerate for 1-2 hours, or until it firms up completely. Break the caramel slice into rough pieces.
The dark chocolate layer is just that- 100% dark chocolate. I found that the 100% dark chocolate was perfect to complement the sweet caramel layer. If you are not a fan of dark chocolate, feel free to add sweetener/sugar to taste. * I often double the batch because I like thick caramel and I use larger crackers