Preheat oven to 350 degrees. Heat 1/4 cup peanut butter in the microwave for about 25 seconds to make it melty. Crush the pretzels in a food processor or however you like to crush pretzels. Any kind of pretzels will do but I recommend using crushed butter pretzels (you find them next to the regular pretzels and they are literally called “Synder Butter Pretzels”) for the recipe. I also recommend not crushing the pretzels to dust but keep some small pieces to keep the crust crunchy. Mix the melty peanut butter, melted butter (melt in microwave), sugar and pretzel crumbs. Press into lightly greased 8x8 pan. Put the pan of pretzel crust in the freezer while you make the cookies. Putting it in the freezer is important for when you try to spread the cookies on top. If you don't chill it, it will be super hard to get the cookie dough evenly over the pretzel crust.