Preheat the oven to 200°F. Line a baking sheet with heavy duty aluminum foil and generously spray with nonstick cooking spray.

Pour the pretzels into an extra large heat safe bowl.

In a 3 to 4 quart saucepan over medium heat, add the light brown sugar, sliced butter pats, and light corn syrup and bring to a low boil, stirring constantly. Allow the mixture to boil for 5 minutes.

Remove the saucepan from the heat and carefully stir in the vanilla extract and baking soda. Be cautious, as the toffee mixture will bubble up and thicken quickly.

Immediately pour the hot mixture over the pretzels. Use a wooden spoon or a silicone spatula to carefully stir the toffee and pretzels together until completely coated.

Use the spoon or spatula to spread the pretzels out on the prepared baking sheet. Sprinkle half of the package of Heath toffee bits over the coated pretzels.

Bake for 1 hour, turning the toffee pretzels in 15-minute intervals.

As soon as the toffee pretzels are removed from the oven, sprinkle the remaining Heath toffee bits over the toffee pretzels.

Allow the toffee pretzels to cool completely before breaking apart.