1. Prepare Oven and Pan; Make and Bake Pretzel Crust:

• Preheat your oven to 350°F (175°C).
• Lightly grease a 9×13-inch baking dish (butter or cooking spray).
• Crush Pretzels: If you haven’t already, crush your pretzels into coarse crumbs. You can do this by placing them in a food processor and pulsing, or by placing them in a sturdy Ziploc bag and crushing them with a meat tenderizer, rolling pin, or even your hands. Measure out 2 ½ cups of the crumbs.
• Mix Crust: In a medium bowl, combine the 2 ½ cups of crushed pretzels, the 4 tablespoons of granulated sugar, and the ½ cup of melted unsalted butter. Stir well with a fork or spatula until all the pretzel crumbs are evenly moistened with the butter and sugar.
• Press and Bake Crust: Press this pretzel crumb mixture firmly and evenly into the bottom of the prepared 9×13-inch baking dish. Use the bottom of a glass or your clean fingertips to create a packed layer.
• Place the pan in the preheated oven and bake the pretzel crust for 10 minutes.
• After baking, remove the pan from the oven and place it on a wire cooling rack to cool completely to room temperature. This is crucial before adding the cream cheese layer.

2. Prepare Pineapple Jell-O Mixture and Cool Slightly:

• While the crust bakes and cools, you can start the Jell-O layer.
• In a large heatproof bowl, add the contents of the two 3-ounce packages of pineapple Jell-O mix.
• Carefully pour 1 ½ cups of boiling water over the Jell-O powder. Whisk continuously for about 2 minutes, or until the Jell-O is completely dissolved.
• Stir in the entire 20-ounce can of undrained crushed pineapple (pineapple and its juice) into the dissolved Jell-O mixture.
• Allow this Jell-O and pineapple mixture to cool on the counter for about 20-30 minutes. You want it to cool down significantly and perhaps just begin to thicken slightly, but not become fully set. It shouldn’t be super hot when poured over the cream cheese layer.

3. Make the Cream Cheese Filling:

• Ensure your cream cheese is fully softened to room temperature and your whipped topping is thawed but still cool.
• In a large mixing bowl, using an electric mixer (handheld or stand mixer), beat the softened cream cheese and the sifted powdered sugar together on medium speed until the mixture is completely smooth and fluffy, with no lumps.
• Gently fold in 8 ounces (half of the larger tub) of the thawed whipped topping using a rubber spatula until it is evenly incorporated and no streaks remain. Be careful not to deflate the whipped topping too much.

4. Layer Cream Cheese Filling on Cooled Crust and Chill:

• Once the pretzel crust is completely cool to the touch, carefully spread the prepared cream cheese mixture evenly over the crust.
• Very Important: Make sure to spread the cream cheese mixture all the way to the edges of the pan, creating a complete seal over the pretzel crust. This barrier is essential to prevent the liquid Jell-O mixture from seeping down into the pretzel base and making it soggy.
• Place the pan with the crust and cream cheese layer into the refrigerator and chill for at least 30 minutes (or while the Jell-O continues to cool/slightly thicken) to allow the cream cheese layer to firm up a bit.

5. Add Pineapple Jell-O Topping and Chill Until Set:

• After the Jell-O mixture (from Step 2) has cooled for 20-30 minutes and is no longer hot (it should be lukewarm or just beginning to show signs of thickening), carefully pour it evenly over the chilled cream cheese layer in the pan.
• Cover the pan carefully with plastic wrap.
• Place the pan back in the refrigerator and chill for at least 2-3 hours, or until the Jell-O topping is completely set and firm.

6. Add Final Whipped Topping and Garnish:

• Once the Jell-O layer is fully set, spread the remaining 8 ounces of thawed whipped topping evenly over the top of the Jell-O layer.
• Return the dessert to the refrigerator to chill for at least another 2 hours (or longer) to allow the final topping to set and all layers to be thoroughly cold.
• Just before serving, garnish the top with the ⅓ cup of broken up pretzel pieces.

7. Serve:

• Cut the Pineapple Pretzel Salad into squares using a sharp knife.
• Serve chilled and enjoy this delightful sweet and salty treat!