1. Preheat oven to 300°F. Line 2 baking sheets with parchment paper.
2. Melt butter in a large saucepan set over medium heat. Add brown sugar, maple syrup, Sriracha, and salt. Bring to a boil, swirling pan to combine. When sugar has dissolved, boil for 2 minutes. Remove from heat. Stir in maple extract.
3. In a large bowl, toss the brown sugar caramel with popcorn, pretzels, cashews and peanuts. Spread evenly on prepared baking sheets. Bake, stirring occasionally, for 20 minutes or until caramel has set. Cool completely and break into clusters.