Peanut Brittle

A one-ingredient caramel with nuts stirred in — no butter, no corn syrup, no soda. It works, but dry-caramelizing sugar demands your full attention for the four or five minutes it takes.

• The hinge: dry caramelSugar melted alone with no water or syrup will clump into hard lumps before it liquefies. Use a heavy skillet or saucepan over medium heat, keep stirring, and let the lumps redissolve; do not raise the heat to hurry them along or the melted portion will scorch while the lumps are still solid.
• Colour is the doneness cuePull the pan off the heat at a medium amber, roughly 340-350F. Sugar goes from amber to acrid black in seconds, and residual heat keeps it cooking after it leaves the burner.
• Warm the nutsCold peanuts dropped into hot caramel cool it fast and can stiffen it before you pour. Toasting them briefly in the oven or a dry pan first warms them and improves flavour; stir them in quickly at the end, as the recipe directs.
• Pan preparationGrease a rimmed sheet pan and have it out and ready before you start; a silicone mat or buttered parchment works better still. There is no time to prepare it once the sugar is melted.
• Marking into squaresThis brittle has no baking soda, so it is dense and glassy rather than aerated and will not snap along scored lines as cleanly as commercial brittle. Score it while it is still flexible, within a minute or two, or simply let it set hard and break it into shards.
• Shelled-nut equivalenceThe closing note is the book helping you shop: 3/4 cup peanuts in the shell yields about 1/4 cup of kernels. Raw or roasted unsalted peanuts both work; salted ones give a pleasant contrast if you want it.
• YieldOne cup of sugar plus a quarter cup of nuts makes only a thin, small sheet — a modest plateful. Double it only if you are confident with caramel, since a larger mass is harder to stir evenly.
• HumidityHard candy of this kind turns tacky in damp air within a day. Store it airtight with the pieces separated by parchment, not in the open dish.