In a bowl, whisk together the melted butter, bourbon, sugar, vanilla paste, paprika, garlic and pepper flakes. Pour it over the pretzels and use your hands to toss everything together really well. Place the pretzels in the oven and bake for 15 minutes. Toss and bake for 10 minutes more. Remove and let cool completely on the sheets. I like to store these in mason jars or even resealable containers or bags. You can dress them up cute for gifting!