In the bowl of a stand mixer fitted with the paddle attachment, beat together the butter, brown sugar and sugar until creamy, about 1 minute. Beat in the egg and egg yolk, then the vanilla. Add in the cornstarch, baking soda, salt and flour until a soft dough forms. Toss in the pretzel crisps, white chocolate chips and caramel bits; beat gently until pretzels are broken up into bite-sized pieces.

Cover and refrigerate the dough for at least 1 hour.

Preheat oven to 350 degrees F. Line 2 baking sheets with silicone liners, parchment paper, or spray the sheets with cooking spray. Drop rounded, heaping Tablespoonfuls of dough onto the baking sheets about 2" apart (I used a 2-Tbsp cookie dough scoop, but you'd get more cookies out of a 1-Tbsp cookie scoop).

Bake for approx. 8-10 minutes, rotating pans halfway through baking time to ensure even cooking. Cool on the sheets for about 10 minutes, then gently transfer to a wire rack to cool completely.