Preheat oven to 300°F (150°C) and line a large baking sheet with parchment paper.
Place pretzels in a large mixing bowl.
In a small bowl, whisk together granulated sugar and ground cinnamon until well combined.
Melt the butter in a microwave-safe dish or small saucepan over low heat.
Pour melted butter over pretzels and gently toss with a spatula until evenly coated.
Sprinkle cinnamon-sugar mixture over the buttered pretzels and toss gently until completely coated.
Spread coated pretzels in a single, even layer on the prepared baking sheet.
Bake for 8-10 minutes, until coating is set and fragrant.
Remove from oven and let cool completely on the baking sheet; pretzels will get crunchier as they cool.
Serve immediately or store in an airtight container at room temperature.
Notes
Be gentle when tossing pretzels to avoid breaking. Ensure pretzels are in a single layer for even baking. Optional: drizzle melted white chocolate over cooled pretzels for extra sweetness.