Old-fashioned English-style toffee, embellished with lots of chocolate and toasted nuts, coconut flakes, and flaky salt. Delicious, easy to make, and great for hostess gifts.
Line a 9x12-inch sheet pan with parchment paper (or use a non-stick pan). Arrange half the toasted nuts in an 8x10-inch rectangle on the sheet pan. Sprinkle half the chocolate chips over the nuts.
Combine the butter, granulated and brown sugars, kosher salt, and 2 Tablespoons of water in a large heavy saucepan (preferably non-stick). Cook over medium-high heat, monitoring the temperature all the while, until the mixture is deep golden brown and the thermometer registers 300°F. Remove the pot from the heat and carefully stir in the vanilla. Sprinkle the baking soda over the surface and stir just to blend.
Working quickly pour the mixture over the nut and chocolate rectangle on the sheet pan. Spread the mixture to smooth if needed. Immediately sprinkle on the remaining chocolate chips. Let stand for a few minutes, then spread the chocolate evenly over the toffee with an offset spatula. Sprinkle on the remaining nuts and press gently onto the softened chocolate. Sprinkle on the sea salt, coconut flakes, or any other embellishments you have chosen to add. Allow the candy to cool completely (at least two hours). When ready to serve or package, break into large, irregular shards. Toffee can be stored airtight at room temperature for several days, or frozen for longer storage.
Adapted from Bon Appetit Magazine.