Remove and discard any unpopped kernels from popcorn. 

In a saucepan over medium heat, combine butter, brown sugar, honey, and salt, stirring constantly. Bring to a simmer, whisk in vanilla, and simmer for 4 to 5 minutes. The longer it cooks, the crunchier the coating will be. 

Put popcorn into a bowl. Pour sauce over popcorn. Gently toss until popcorn is evenly coated. Sprinkle with toffee bits and stir until evenly incorporated. 

Store in an airtight container.