Yield: Makes 4-1/4 pounds of toffee (100 pieces measuring 1 x 2 inches)
- 1 pound (4 sticks) butter
- 1 cup granulated sugar
- 1 cup firmly packed golden brown sugar
- 1 tablespoon light corn syrup
- ¼ cup water
- 2-½ cups raw hazelnuts, coarsely chopped
- 2 teaspoons vanilla extract
- ¼ teaspoon salt
- 16 ounces semi-sweet chocolate
- (either chips, or squares that have been broken into chunks)
- 2 cups chopped dark-roasted and skinned hazelnuts
Grease one large (12 x 17- inch) rimmed baking sheet or two smaller (10 x 15-inch or less) ones with butter.
Melt the pound of butter in a large, heavy-bottomed pot over medium heat on a wide-diameter burner. While the butter is melting, combine the granulated sugar, brown sugar and corn syrup. Add this mixture to the melted butter, along with the water. When the sugars have dissolved, increase the burner setting to medium high, stirring with a flat-edged wooden spoon. Attach a candy thermometer to the pot and cook the mixture, stirring constantly to keep it from scorching. When the temperature reaches 240 ° F, add the nuts and continue stirring. At 260 °, reduce the burner setting to medium-low and continue cooking and stirring occasionally, until the toffee reaches 300 ° (“hard crack”).
Remove the pot from the burner and stir in the vanilla and salt, stirring quickly because the toffee will become quite thick at this point. Scrape it out onto the prepared baking sheet(s) or marble slab, spreading it out to a thickness of about ¼ to ½ inch. A silicon spatula is the best tool for spreading the sticky toffee.
Allow the toffee about 5 minutes to set up, then distribute the chocolate pieces evenly over the surface. The heat from the toffee will melt them. While it’s still soft, gently even out the layer of chocolate and then sprinkle it with the roasted and chopped hazelnuts.
At this point, you can refrigerate the toffee until it is cold and hard. Or you can just let it cool to room temperature over several hours or overnight. Once the toffee is very firm, it can be broken into smaller, irregular-sized pieces.
NOTE: If you use unsalted butter, increase the amount of salt in the recipe from ¼ teaspoon to 1 teaspoon.