This is my all-time favorite holiday treat – every year I make a big batch and eat about half of it, then loll around on the couch for the rest of the day (not a winning formula, I know). The combination of buttery toffee, crunchy toasted almonds and dark chocolate is more than slightly addictive. If you can somehow manage not to eat most of it, it also makes a wonderful gift, particularly when wrapped in a cellophane bag that is finished with a festive ribbon.

Makes about 1 ½ pounds

Special equipment: candy thermometer

Ingredients

2 cups (240 grams) blanched slivered almonds
7 ounces (198 grams) bittersweet chocolate (64 to 70%)
12 tablespoons (170 grams) unsalted butter, cut into tablespoons
¼ teaspoon fine salt
2 tablespoons (30 grams) water
1 cup (200 grams) granulated sugar
¾ cup (162 grams) firmly packed light brown sugar
¼ teaspoon baking soda
1 teaspoon vanilla paste or extract
3/4 teaspoon flaky sea salt, such as fleur de sel or Maldon sea salt

Instructions

Preheat the oven to 350°F.

Place the almonds on a baking sheet and bake for about 8 minutes, until lightly golden and fragrant. Cool.

Set aside half of the toasted nuts (these will be stirred into the toffee layer). Place the remaining nuts in a food processor and pulse until they are finely chopped. Set aside (these nuts will be used to sprinkle on top of the chocolate layer).

Finely chop the chocolate and set aside.

Brush the bottom of a 10-by-15-inch rimmed baking sheet with vegetable oil. Use a paper towel to wipe off any excess oil so that the sheet is lightly coated.

Put a small bowl of water and a brush next to the stove (this will be used for washing down the sides of the pan during cooking). In a medium, heavy-bottomed saucepan, combine the butter, salt, water and both sugars and cook over medium heat, stirring gently just until the butter is melted. Increase the heat to medium-high, insert a candy thermometer, and cook, without stirring, until the mixture registers 298°F, occasionally brushing down the sides of the pan with water to prevent sugar crystals from forming. Remove the pan from the heat and immediately stir in the unchopped almonds, then the baking soda and vanilla. Once blended, immediately pour the hot toffee onto the baking sheet, using a small, offset metal spatula to spread it evenly into a rectangle that is roughly 8-by-13 inches. While the toffee is hot, sprinkle the finely chopped chocolate over it in an even layer. Let the chocolate sit for 1 minute to melt. Then, using a small offset metal spatula, spread it over the toffee, covering it completely. Sprinkle the finely chopped nuts and the coarse salt over the melted chocolate. Refrigerate the toffee for 30 minutes, or just until the chocolate is no longer shiny and is set.