Butterscotch begins to solidify immediately after it’s cooked and may be scored or shaped before it cools. Work quickly for best results.

Line a large baking sheet with a silicone liner or well-buttered heavy-duty foil, leaving a 2-inch overhang of foil at the two short ends of the pan.

Combine in a large heavy saucepan:

Stir over medium heat until the sugar is dissolved. Wash down the sides of the pan with a pastry brush dipped in warm water. Increase the heat to medium-high and stir constantly until the mixture comes to a boil. Cook, swirling the pan as needed to prevent hot spots, to 300°F, the hard-crack stage. Pour the candy onto the prepared pan. Do not scrape the bottom of the saucepan. Let cool for 3 to 4 minutes.

Score the candy into 1-inch pieces with a buttered knife. Let cool completely.

Break the butterscotch into pieces along the scored lines. Wrap each piece in cellophane, or store between layers of wax or parchment paper in an airtight container at room temperature for up to 1 month.