Preheat your oven to 350°F (175°C). Grease a 9x13 inch baking pan or line it with parchment paper.
In a medium saucepan, melt the unsalted butter over low heat. Allow it to cool slightly after melting.
In a large mixing bowl, combine the melted butter and granulated sugar. Whisk until blended. Add the eggs one at a time, mixing well after each addition, followed by the vanilla extract.
In a separate bowl, sift together the flour, cocoa powder, baking powder, and salt.
Gradually add the dry ingredients to the wet mixture, stirring gently until just combined.
Fold in the crushed pretzels and chocolate chips into the brownie batter until evenly distributed.
Pour the batter into the prepared baking pan and spread it out evenly. Bake for approximately 25-30 minutes.
While the brownies are baking, prepare the caramel sauce if making homemade or warm the store-bought caramel sauce.
Once the brownies are done, drizzle caramel sauce over the top while still warm.
Sprinkle flaky sea salt evenly over the caramel.
Allow the brownies to cool in the pan for at least 1 hour before slicing into squares.
Cut the brownies into squares and serve. Drizzle additional caramel sauce on top if desired.
Notes
Serve with extra caramel sauce and whole pretzels for garnish.