Macadamia Milk Chocolate Toffee

2 cups sugar
1½ cups (3 sticks) unsalted butter, cut into pieces
1 cup (4 ounces) macadamia nuts, rinsed of any salt if salted and patted dry, coarsely chopped
1 cup (6 ounces) milk chocolate chips

Make a batch of this buttery, crunchy toffee for gift giving, and you may end up keeping a good bit of it for yourself.

Lightly butter a 15½ × 10½ × 1-inch jelly-roll pan. In a large, heavy-bottomed saucepan cook the sugar and butter over medium heat, stirring constantly, until the mixture comes to a boil.
Attach a candy thermometer to the pan. Cook, stirring constantly at a steady but not rapid pace until the syrup reaches 310°F, about 15 minutes. Remove the pan from the heat and stir in ½ cup of the macadamia nuts. Pour the mixture into the prepared pan, letting it spread naturally. Let stand for 5 to 10 minutes to cool slightly. The chocolate must be warm enough to melt the chocolate topping, so don’t let it cool too much.
Using a lint-free kitchen towel, blot any butter that has separated out of the toffee (a small amount is to be expected, but if a lot separates, it means you cooked the toffee too quickly). Sprinkle the chocolate chips in a single layer over the surface of the hot toffee. Let stand until the chocolate softens, about 5 minutes. Using a metal spatula, spread the chocolate evenly over the surface of the toffee. Sprinkle with the remaining ½ cup macadamia nuts. Using a large, sharp knife, score the toffee into 2-inch pieces. As the toffee cools, retrace the score lines occasionally with the knife to reach the bottom of the pan so the toffee will break apart easily.
When the toffee is cooled and the chocolate is firm, use a metal spatula to remove the toffee from the pan. Following the score lines, break into pieces and serve.