About 8-ounces(227g)mini pretzels, (half of a 1-pound bag) broken into smaller pieces, more or less to cover the pan
1cup(212g)packed light brown sugar
2cups(340g)semisweet chocolate chips
Preheat the oven to 375 degrees F. Line an 11X17-inch rimmed baking sheet with aluminum foil or parchment paper. Cover the bottom of the pan in a layer of broken mini pretzels. Set aside.
In a small or medium saucepan over medium heat, combine the 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 back and forth motion to cover most of the pretzels (a few empty/dry spots are ok as the caramel will fuse together during baking).
Bake for 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 2-3 minutes until they melt. Use an offset spatula or rubber spatula to gently spread the melted chocolate over the toffee. Lightly sprinkle with sea salt.
Let the toffee cool completely at room temperature then refrigerate if needed to help the chocolate set up. Break the toffee into pieces and try not to eat the whole batch.
Chocolate: my preferred brand of chocolate is Ghirardelli.