1 cup butter
1 cup sugar
1 tbsp water
1 tsp light corn syrup
1/2 tsp salt
8 oz good quality semisweet chocolate
1 cup (+) of pistachios
In a heavy pot, put the butter, sugar and water. Over medium-high heat, melt the butter. When it is melted, add the syrup and salt. Stir. Add a candy thermometer.
Stir occasionally to keep well mixed. When the temperature has reached 265 degrees, begin stirring constantly until it reaches 290 degrees. When it reaches 290, pour immediately onto a silpat lined baking sheet (or a very well buttered sheet). Spread out quickly. Put on 8 oz of good quality semisweet chocolate and let sit 2 minutes. Then, spread the melted chocolate over the entire toffee right up to the edges. Immediately sprinkle on about 1 cup (or more if you wish) of pistachios.
Let set until completely cooled and then break into chunks. Store in a well sealed container in your refrigerator for up to 2 weeks. Or freeze for up to 3 months.