Preheat oven to 300°F (150°C). Line a large baking sheet with parchment paper or a silicone baking mat. Spread the chopped pecans on top and toast for 7-8 minutes or until fragrant and lightly browned. Set aside. 1 cup will be used inside the toffee and the rest are sprinkled on top.

While stirring with a wooden spoon, melt the butter over medium heat in a 3-quart heavy-duty saucepan. Once melted, add the water, 1 cup (200g) granulated 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 the bulb is not touching the bottom of the pan (as you’ll get an inaccurate reading).

Stir the mixture every minute as it begins to boil. Rapid bubbles, a thicker consistency, and a slightly darker color form around 240°F (116°C). Continue to stir every minute until it reaches 290°F (143°C; soft crack stage). Be watchful—the temperature slowly rises in the beginning, but then skyrockets quickly. If you notice it’s rising very fast, you can even turn off the heat when the toffee reaches 285°F (141°C), as it will continue to cook in the few seconds after.

Immediately remove the pan from heat and stir in 1 teaspoon pumpkin pie spice and 1 cup toasted pecans. Pour the toffee out onto a silicone baking mat lined baking sheet. Smooth into an even layer. The toffee should be thick and not spread all the way to the edges of the pan. Cool the toffee for 5 minutes.

Meanwhile, get the toppings ready. Mix the remaining 1 Tablespoon of granulated sugar with the remaining 1/4 teaspoon of pumpkin pie spice. Melt the white chocolate. You can melt it in a double boiler or use the microwave. I melt it in the microwave in 20 second increments, stopping and stirring after each.

Spread the melted white chocolate on top of the toffee, then sprinkle with remaining pecans and sugar/pumpkin pie spice mix.

Refrigerate toffee for 20 minutes or until white chocolate has set. Peel off the silicone baking mat and break toffee into pieces.

Store toffee in an airtight container at room temperature in a cool dry place for up to 2 weeks.