Step 1

In a large heavy bottomed saucepan, combine the butter, sugar and salt. Cook over medium heat, stirring until the butter is melted. Allow to come to a boil, and cook until the mixture becomes a dark amber color, and the temperature has reached 285 degrees F (137 degrees C). Stir occasionally.

Step 2

While the toffee is cooking, cover a large baking sheet with aluminum foil or parchment paper.

Step 3

As soon as the toffee reaches the proper temperature, pour it out onto the prepared baking sheet. Sprinkle the chocolate over the top, and let it set for a minute or two to soften. Spread the chocolate into a thin even layer once it is melted. Sprinkle the nuts over the chocolate, and press in slightly. Putting a plastic bag over your hand will minimize the mess.

Step 4

Place the toffee in the refrigerator to chill until set. Break into pieces, and store in an airtight container.