Preheat your oven to 400° and line a baking sheet with parchment paper.
In a large bowl, stir together crushed pretzels, melted butter, and ½ cup sugar.
Spread the pretzel mixture out evenly across the prepared baking sheet.
Bake in the oven for 7 minutes.
Remove from the oven and place on wire cooling rack to let cool completely.
Place cream cheese in a large mixing bowl or in the bowl of a stand mixer. Using an electric mixer beat the cream cheese until creamy and fluffy.
Mix in remaining ½ cup sugar and continue beating until well mixed.
Add the crushed pineapple to the cream cheese mixture and mix on low until well incorporated.
Next mix in the cool whip, until well combined.
Fold in the cooled crushed pretzels, reserving 1/4 cup if desired for topping the fluff.
Serve immediately or store covered in the refrigerator until ready to serve.