Preheat oven to 350 degrees. Line a 9" x 13" baking dish with foil and spray lightly with cooking spray to prevent sticking.
In a medium sized bowl, whisk together flour and salt. Set aside.
Set aside about 2 tablespoons of the caramel sauce.
In a stand mixer with the paddle attachment, or in a large bowl with a hand mixer, beat butter, sugar and the remaining caramel sauce until light and fluffy; about 2 minutes. Scrape the sides of the bowl with a spatula. Beat in eggs and vanilla until well combined.
Stir in flour mixture just until combined. Fold in about 2 1/4 cups of the crushed pretzels.
Spread batter evenly in the prepared baking dish. Sprinkle remaining crushed pretzels on top.
Bake in the preheated 350 degree oven for about 35-40 minutes, or until top is golden brown and a toothpick inserted into the center comes out clean.
Cool for about 10 minutes in the dish, then use the foil to lift out to a wire rack to cool completely. Once blondies are completely cool, drizzle with the 2 tablespoons of caramel sauce.