Preheat your oven to 350°F (180°C). Line an 8x8-inch (20x20 cm) baking pan with parchment paper for easy removal.
For the pretzel bottom, crush the pretzels in a food processor or place them in a zip-top bag and crush with a rolling pin until fine crumbs form.
In a bowl, combine the pretzel crumbs, 2 tablespoons of granulated sugar, and melted butter. Mix until everything is moistened.
Press this mixture firmly into the bottom of the prepared pan. Place the pan in the fridge to set.
For the brownies, melt the ½ cup of unsalted butter in a saucepan over low heat.
Remove from heat and stir in the chopped dark chocolate until completely melted and smooth.
Allow it to cool slightly.
In a separate bowl, whisk together the flour, sifted cocoa powder, and salt.
Using an electric mixer, beat the eggs, both sugars, and vanilla extract on high speed for about 5 minutes.
Pour in the cooled chocolate mixture and mix for an additional minute.
Gently fold in the dry ingredients using a rubber spatula until just combined.
Remove the pan from the fridge and pour the brownie batter over the pretzel crust.
Bake for about 25 minutes, checking for doneness with a toothpick.
While the brownies are baking, prepare the caramel.
In a medium saucepan over medium heat, melt the granulated sugar, stirring constantly.
Once melted, quickly add the butter and whisk until combined.
Stir until the butter is fully melted, then slowly pour in the heavy cream while whisking.
Allow the mixture to boil for 1-2 minutes.
Let the caramel cool for about 5 minutes, then pour it evenly over the brownies.
Allow everything to cool completely, ideally for 6-7 hours or overnight, before cutting into squares.