Preheat the oven to 350° degrees F and line a 9x13-inch baking pan with a piece of parchment paper.

Add butter and chocolate to a medium saucepan and melt over low heat. 

Stir in the cocoa powder and whisk to dissolve the cocoa in the warm mixture. 

Remove from heat and stir in the sugar and vanilla. 

Add the eggs, one at a time, whisking constantly between each addition. 

Fold in the flour, instant espresso powder, and dark chocolate chips. 

Lightly crush half of the pretzels and fold those into the brownie batter.

Pour the brownie batter into the prepared baking pan. 

Arrange the remaining pretzels on top of the brownie batter. 

Bake until brownies are mostly set, yet slightly gooey in the middle, 40-45 minutes.

Start checking doneness at 35 minutes with a toothpick – it should come out clean with moist crumbs and not completely dry. 

Allow the brownies to cool completely before slicing and serving. Enjoy!