Blend the sugar, salt, pepper, and cinnamon in a bowl.

Finely grind the star anise, cloves, and Szechwan peppercorns in a spice grinder.

Strain the ground spices through a fine mesh sieve to remove husks and combine with the sugar mixture.

Heat a large heavy skillet, preferably cast iron, over high heat until a bead of water evaporates on contact.

Add the nuts to the hot skillet and toss until heated through, about 1 minute.

Reduce heat if needed to prevent scorching.

Sprinkle the nuts with half the seasoning mixture and shake the pan until the sugar melts and caramelizes to a dark brown, about 1 minute.

Add the remaining seasoning mixture and continue shaking until the sugar melts and coats the nuts.

Do not use a spatula or spoon, as the sugar will stick to it instead of the nuts.

Immediately transfer the caramelized nuts onto a foil-lined baking sheet.

Separate the nuts with your fingers while they are still warm enough to handle.

Let the nuts cool completely.

Store in a tightly sealed, clean, dry glass jar.