Preheat oven to 150°C fan bake and line two large oven trays with baking paper.
Arrange peanuts and almonds in a single layer on one of the prepared trays. Bake for 12 minutes, stirring halfway, until lightly toasted.
Meanwhile, place pretzels and crackers in a large bowl.
Place Tararua Butter, Chelsea Dark Cane Sugar, Chelsea Golden Syrup, garlic powder, cumin, salt and cayenne pepper in a microwave-safe jug. Microwave in bursts of 20 seconds, stirring in between, until butter has melted and sugar has dissolved. Whisk until well combined.
Add 3 tablespoons sauce to the nuts and toss to combine. Return to oven and cook for 10 minutes, stirring halfway through.
Add remaining sauce to pretzels and crackers. Toss to combine. Arrange in a single layer on second prepared tray. Place in oven (transfer nuts to a lower shelf and place above nuts) and bake for 10-15 minutes, tossing halfway, until well toasted. Keep a close eye on them as the pretzels and crackers can burn easily.
Leave to cool on trays, then transfer to airtight containers or jars. Snack mix keeps well for at least 2-3 weeks.