(If your pecans are raw heat the oven to 300F, place the pecans on a baking sheet and toast for about 5 minutes. Increase oven temperature to 350F.)
Preheat oven to 350 degrees F. Lightly grease a 13x9 baking pan. Line the pan with parchment paper so that the paper is along the bottom and long enough for handles up the two longer sides of the pan.
In a medium-size microwave-safe bowl place the butter, chocolate chips, and instant espresso. Microwave on high for 30-second intervals, stirring after each interval until melted smooth. Let cool.
In a large bowl whisk the eggs, sugar, and vanilla until combined. In a small bowl whisk the flour, baking powder, and salt. Stir cooled chocolate mixture into the egg mixture. Add the flour mixture in 2 additions until just combined.
Pour half of the brownie batter into the prepared pan. Spread evenly to cover the bottom of the pan. Bake for 10 minutes.
While the first layer is baking: in a medium-size bowl add the caramels, heavy cream, and salt. Microwave on high for 30-second intervals, stirring after each interval until melted and smooth. Let cool.
Remove the first layer of brownie from the oven, sprinkle the pecans in an even layer over the top and slowly pour the cooled caramel over the pecans.
Spoon the remaining brownie batter over the caramel, carefully spread the batter as best as you can over the caramel. Don't worry if it doesn't go the edges completely. While it bakes it will spread out and evenly cover.
Bake at 350ºF for 25-30 minutes or until almost set in the middle. They may appear slightly under-cooked, it's ok. Do not over-bake or it will dry out the brownies.
Cool the brownies completely before removing from the pan and cutting into squares. Some caramel may have baked to the edges of the pan and you might need to run a knife around to loosen them before lifting out of the pan.Slice and serve!