First, In a small bowl, microwave the 1 cup of chocolate chips and butter on 30 second increments, mixing well after each one. Careful not to burn.
Set aside to cool.
Preheat oven to 350 ℉
Line a 9x9 baking dish with parchment paper.
Then, in a mixer, combine the egg yolk, eggs, brown sugar, regular sugar, salt, oil, vanilla extract, and mix on medium until well combined.
Next add cocoa and espresso powder and mix again.
Add the flour and mix until combined.
Pour the melted chocolate into the mixer and mix on medium until just combined.
Then fold in the pecans, chocolate chunks and remaining chocolate chips using a rubber spatula.
Top with additional crushed pecans and crushed chocolate.
Bake for 38-45 minutes until the edges harden slightly and a toothpick comes out clean.
Remove from the oven and allow the brownie to cool for 90 minutes before removing from the pan and slicing. Top with salted caramel sauce.