Skewer each apple on a stick by inserting the stick directly through the core from the top of the apple. Dip an apple in the toffee, coating evenly. Then hold the apple up and slowly twirl it to allow the toffee to cool in an even coating. Once the toffee has started to cool, place the apple, stick side up on a sheet of baking paper (shiny side facing up). Repeat until you have 4 apples covered in toffee.