Preheat your oven to 350°F (175°C). Grease and line a 9×13 inch baking pan with parchment paper.

In a large mixing bowl, whisk together the melted butter and brown sugar until smooth and creamy.

Add the eggs and vanilla extract to the mixture and whisk until well-combined.

In another bowl, whisk together the flour, baking powder, baking soda, and salt.

Gradually fold the dry ingredients into the wet mixture. Be careful not to overmix—just stir until no flour is visible.

Gently fold in the chopped pretzels and half the salted caramel sauce until evenly distributed.

Spread the batter into the prepared pan, smoothing it out evenly.

Drizzle the remaining salted caramel sauce over the top of the batter and swirl it in slightly with a knife.

Bake in the preheated oven for about 20-25 minutes or until the edges are golden brown and a toothpick comes out slightly moist from the center.

As soon as you remove the blondies from the oven, sprinkle with flaky sea salt. Allow to cool completely in the pan before slicing.