Preheat oven to 375°F.

Line an 11 X 17-inch rimmed baking sheet with aluminum foil or parchment paper. Cover the bottom of the pan with a layer of broken mini pretzels. Set aside.

In a small or medium saucepan over medium heat, combine butter and brown sugar. When the mixture starts to gently simmer and bubble, let it cook for 3 minutes without stirring.

Immediately pour the hot caramel mixture over the pretzels in a forward and backward motion to cover most of the pretzels. A few empty/dry spots are ok as the caramel will fuse together during baking.

Bake 5 minutes.

Remove the pan from the oven and place the pan on a cooling rack. Immediately sprinkle chocolate chips evenly over the top of the hot caramel and pretzels.

Let the chocolate chips sit for 2 to 3 minutes until melted.

Use a spatula to gently spread the melted chocolate over the toffee. Lightly sprinkle with sea salt.