In large bowl, whisk together half of the sugar and all of the cinnamon. Add the melted butter and combine. Add the pretzels and toss to combine. I recommend doing this in batches to keep the pretzels from breaking and to ensure an even coat of the cinnamon mixture. Put the pretzels in a single layer on a lightly oiled cookie sheet(s). Sprinkle with the remaining half of the sugar. Bake at 250 degrees for 10 minutes. YUM!