Preheat your oven to 300°F (150°C) and line a large baking sheet with parchment paper or a silicone baking mat.

Spread the chopped pecans over the baking sheet and toast them for 7-8 minutes until fragrant and lightly browned. Set aside 1 cup for the toffee and the rest for topping.

In a heavy-duty 3-quart saucepan over medium heat, melt the butter, stirring continuously.

Once melted, add warm water, 1 cup granulated sugar, salt, and light corn syrup. Stir until sugar dissolves, brushing down the sides with a moistened pastry brush.

Attach a candy thermometer to the pan and bring to a boil, stirring every minute until it thickens and reaches 240°F (116°C).

Continue cooking until it reaches 290°F (143°C) for soft crack stage, watching closely to prevent burning.

Remove from heat and stir in 1 teaspoon of pumpkin pie spice and 1 cup of toasted pecans.

Pour the toffee onto the baking sheet, smoothing it into an even layer, and let it cool for 5 minutes.

While cooling, combine remaining 1 tablespoon of granulated sugar with remaining 1/4 teaspoon of pumpkin pie spice.

Melt white chocolate in a double boiler or microwave, stirring until smooth.

Spread melted chocolate over the toffee, then sprinkle with leftover pecans and sugar-pumpkin spice mixture.

Chill in the refrigerator for 20 minutes or until chocolate sets.

Once firm, peel from the mat and break into pieces. Store in an airtight container.