Sponge Toffee with Chocolate

1 cup granulated sugar
1 cup light corn syrup
1 tablespoon white vinegar
1/4 teaspoon salt
1 tablespoon pure vanilla extract
1 tablespoon baking soda
1 tablespoon unsalted butter
3 ounces chocolate, melted

Spray or butter a 9-inch springform pan with 3-inch-high sides with nonstick cooking spray.

In a large, heavy bottomed pot, combine the sugar, corn syrup, vinegar and salt. Stir to combine over medium-high heat. When the mixture reaches a boil, clip a candy thermometer onto the side of the pot. Cook the syrup, stirring often, until it reaches 295 degrees. Remove the pot from the heat, and quickly stir in the vanilla. Stir in the baking soda until the candy is smooth. Add the butter and stir until melted. Pour the candy into the prepared pan and let set until cool, about 1 hour.

Melt chocolate in a double boiler, and slather the chocolate all over the top of toffee.
Cool another hour and slice into chunks.

Candy will store in an air tight container for up to a week.