Preheat oven to 350 degrees F. Lightly coat an 8×8 baking dish with nonstick spray; then line baking dish with parchment paper.
In a large bowl, whisk together butter, brown sugar, egg and vanilla. Add flour, stirring just until incorporated. Add pretzels and gently toss to combine.
Spread batter into prepared baking dish and drizzle with caramel sauce.
Place into oven and bake for 28-32 minutes, or until a tester inserted in the center comes out clean.
Remove from oven and cool on a wire rack. Drizzle with caramel sauce and sprinkle with salt, if desired.
Let cool completely before cutting into bars.
