Prepare a baking sheet with a silicone baking mat or greased parchment or wax paper.
In a large sized heavy-bottomed sauce pan, with a candy thermometer attached, bring all the ingredients, excluding the chocolate, to a boil over medium low heat.
Continue to cook and stir the mixture until it reads 275 degrees F on the candy thermometer.
The mixture will be much thicker. Stir constantly until it reaches 315 degrees F, which will happen pretty quickly. Remove it from the heat and stir until very smooth, just a few seconds.
Pour the toffee onto the prepared baking sheet.
Using a spatula, spread the toffee out, working quickly because the toffee will set fast.
Using a pastry wheel or pizza cutter, VERY GENTLY (you don't want to cut so deep that it actually reaches the bottom or you may destroy your silpat) score the toffee into bite sized pieces.
You should get about 72 pieces. Again work quickly so the toffee doesn't set before you are done.
Allow the toffee to sit until it is room temperature and then break apart the pieces.
Melt the chocolate over a double boiler until perfectly smooth. Remove from the heat and allow to cool to just above room temperature. If the chocolate is too hot it will run off the toffee and not give you a nice coating, if it is too cold it will be too thick to work with.
Set up a second baking sheet with a sheet of parchment or wax paper.
Drop a piece of the toffee into the chocolate. Use a fork to flip the toffee over to coat the other side.
Lift the covered toffee from the chocolate and shake gently to allow the excess to fall away.
In order to get a nice smooth bottom, you want to scrape the bottom of the fork on the edge of the bowl, before laying it on the parchment to harden.
If you want to sprinkle with toasted nuts and sea salt, this is the time.
Continue dipping until they are all covered in chocolate. Allow them to sit out in a cool spot to set up or you can set them in the refrigerator for a few minutes until they are firm.
Fill decorative bags as gifts for Valentine's Day.
Recipe courtesy Zoe Francois