Line a baking sheet with parchment paper and set aside.

Pour the maple syrup into a large heavy-based saucepan on medium-high heat and bring to the boil. Add pumpkin pie spice and salt and stir well.

Slowly pour in all of the nuts and seeds and stir to combine with the spiced syrup. Cook for about 3 - 5 minutes until they have caramelized.

Carefully spread the mixture in an even layer on the prepared baking sheet and set aside to cool. The nuts and seeds will harden.

When nut mixture has cooled, break into clusters in a bowl and add the dried fruit and peanut butter chips if using.

Enjoy immediately, or transfer to an airtight container. The trail mix will keep for about a month.