Ingredients
Equipment
Method
- Start by preparing your pan. Line a rimmed baking sheet with parchment paper or a silicone baking mat so the toffee can be poured out easily and removed once it cools.
- Melt the butter by placing it in a small, heavy bottom saucepan over medium heat. Let it melt slowly and gently, since using high heat can cause the mixture to separate.
- Add the sugar and salt once the butter has mostly melted. Stir in the brown sugar and salt, then whisk briskly for a full minute until the mixture looks smooth and well blended. The sugar may not be completely dissolved at this stage, and that is perfectly fine.
- Continue cooking over medium heat, stirring nonstop and making sure to scrape along the edges so no sugar sticks or burns. The mixture will start to bubble and thicken, taking on the look of smooth, melted peanut butter. Important: Stay right by the stove and keep stirring the entire time. Toffee can burn fast if it is left alone, even briefly.
- If the mixture separates at any time, take the pan off the heat and whisk it briskly until it comes back together and looks smooth. Then return it to medium heat and continue cooking, stirring constantly, until it is finished.
Check for doneness:
- With a candy thermometer, cook until the mixture reaches 295°F to 305°F, which usually takes about 8 to 10 minutes.Without a thermometer, rely on sight and smell. It is ready when the mixture looks very smooth and glossy, turns a deep golden brown color, and gives off a rich, toasted caramel scent.
- Pour and spread: Carefully pour the hot toffee onto the prepared pan right away. Use a spatula to spread it into an even layer. Work gently since the mixture is extremely hot. Let it sit undisturbed for about 20 minutes, or until completely cool and firm.