Prep time: 40 minutes
Total time: 1 hour, 15 minutes
Makes: 1 pound (454g)
large baking sheet
12 x 17-in (30 x 43cm) jelly roll pan or a similar-sized rimmed baking sheet
silicone baking mat (recommended)
3-qt (2.8L) heavy-duty saucepan
1. Preheat oven to 300°F (150°C). Line a large baking sheet with parchment paper and a 12 x 17-in (30 x 43cm) jelly roll pan with a silicone baking mat or lightly butter or spray with nonstick cooking spray. Spread the chopped pecans onto the baking sheet and toast for 7–8 minutes, or until very lightly browned. Set aside.
2. Melt the cubed butter over medium heat in a 3-qt (2.8L) heavy-duty saucepan, stirring occasionally (about every 2 minutes) with a wooden spoon. Once melted, add the water, 1 cup (200g) of sugar, salt, and corn syrup. Stir constantly until the sugar dissolves, then brush down the sides of the pan with a water-moistened pastry brush. Attach a candy thermometer to the pan, making sure not to let it touch the bottom.
3. Once the sugar has dissolved, bring the mixture to a boil. Rapid bubbles, a thicker consistency, and a slightly darker color form around 235°F (113°C). Stir lightly once every minute until the candy reaches 290°F (143°C; soft crack stage).
4. Remove pan from the heat and stir in the pumpkin pie spice and 1 cup of the toasted pecans. Pour the toffee out onto the prepared jelly roll pan. Smooth into an even layer with a wooden spoon. The toffee should be thick and not spread all the way to the edges of the pan. Allow the toffee to cool for 5 minutes, then sprinkle the top with white chocolate. Allow the white chocolate to soften and melt from the heat of the toffee, then spread the melted white chocolate into an even layer using a rubber spatula or the back of a spoon. Sprinkle the top with remaining toasted pecans.
5. Quickly mix the cinnamon and remaining 2 tablespoons (25g) of sugar together in a small bowl. Sprinkle on top. Refrigerate for 20 minutes, or until white chocolate has set.
6. Once set, remove toffee from the refrigerator. Cut, using a sharp knife, or break into pieces as large or small as you want.
Make-Ahead Tip: Store toffee in an airtight container at room temperature in a cool, dry place for up to 2 weeks. For longer storage, freeze up to 3 months and thaw overnight in the refrigerator before serving.