Preheat the oven to 350°F. Grease a 9″ x 13″ pan and set aside.
In a medium-sized saucepan set over low heat, melt the butter, then add the sugar and stir to combine. Stir until mixture is shiny, but do not let it bubble or boil. Remove from heat and pour the mixture into a large bowl.
Stir in the cocoa, baking powder, sea salt, and vanilla extract.
Stir in the eggs and stir until smooth. Add the flour, chocolate chips, and chopped pretzels.
Pour half of the batter into prepared pan. Drizzle the salted caramel sauce evenly over the brownie batter. Top with the remaining brownie batter and smooth with a spatula. Top with whole pretzels and sprinkle with additional sea salt.
Bake the brownies for about 30-35 minutes, or until they are set and a toothpick inserted into the center comes out clean, or with just a few moist crumbs clinging to it. Remove pan from the oven and cool on a rack. Cut into squares and serve.
Note-the brownies will keep in an airtight container in the refrigerator for 3-4 days. Bring to room temperature before serving. I like to eat them cold too:) They are also great served with a scoop of ice cream and extra caramel sauce.