Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
Spread the mini pretzels evenly on the lined baking sheet.
In a saucepan over medium heat, melt the butter. Once melted, stir in the brown sugar. Continue stirring until the mixture is bubbly and the sugar is dissolved, about 3-5 minutes.
Remove the saucepan from heat and stir in the vanilla extract.
Pour the butter toffee mixture over the pretzels, using a spatula to ensure they are evenly coated.
Bake in the preheated oven for 8-10 minutes, or until the pretzels are slightly puffed and glossy.
Remove the baking sheet from the oven and immediately sprinkle the chocolate chips over the hot pretzels. Let them sit for 5 minutes to soften.
Once softened, use a spatula to spread the chocolate evenly over the pretzels.
Sprinkle a pinch of sea salt over the chocolate for an added flavor contrast.
Allow the pretzels to cool completely before breaking them into pieces.
Notes
Allow to cool completely before breaking into pieces for best texture.