Step 1

Preheat oven to 200° degrees F. Lightly grease a large roasting pan with cooking spray; I use a disposable one for easy cleanup. Add the pretzels to the roasting pan; set aside.

Step 2

In a medium saucepan, add the brown sugar, cubed butter, and corn syrup and bring to a boil over medium heat. Boil for 5 minutes, stirring constantly. Remove from the heat and whisk in the vanilla extract and baking soda; the toffee will bubble violently - this is normal.

Step 3

Pour the hot toffee mixture evenly over the pretzels; sprinkle half of the bag of toffee bits over the pretzel mixture, too. Toss the pretzels to coat evenly in the toffee mixture and toffee bits.

Step 4

Bake for 1 hour, stirring every 15 minutes to ensure the hot toffee mixture evenly coats the pretzels. Once baked, spread the pretzel mixture onto a wax paper-lined countertop and immediately sprinkle with the remaining toffee bits. Allow the pretzels to set and harden, about 1 hour, before breaking into smaller clusters and packaging.