Preheat the oven to 350 degrees and grease an 8 x 8 pan (or line one with parchment paper) and set aside.
To make the shortbread
In a small bowl, whisk together the flour and cocoa powder.
To a large bowl, add the butter, sugar, and salt and mix on medium speed with a hand mixer until smooth.
Add the dry ingredients and beat until the dough comes together. Be patient with this step, it will take a few minutes.
Pour into the prepared pan and press down evenly.
Bake for 10 minutes, rotate the pan, then bake another 10-13 minutes or until the edges are slightly darker than the center.
Remove from the oven and allow to cool completely while you're making the caramel.
To make the caramel
To a medium saucepan, add the sugar, water, and corn syrup and bring to a boil over medium-high heat.
Allow the mixture to bubble (brush down the sides of the pan with cold water with a silicone brush if there are splatters), swirling a couple times once the mixture turns a pale to medium amber color.
Lower the heat then add the cream, then butter and salt. The caramel may roil.
Take the pan off the heat and drop in the chopped chocolate, Stir with a silicone spatula to combine.
Pour the hot caramel over the cooled shortbread then sprinkle with the toasted pecans. Allow to set at room temperature.
Once cooled, cut into 21 bars.