. Prepare the Crust
Preheat the oven to 350°F (175°C).
Lightly coat a 9×13-inch baking dish with nonstick cooking spray.
In a medium bowl, combine the crushed pretzels and ½ cup sugar.
Stir in the melted butter until fully coated.
Press the mixture firmly into the bottom of the prepared baking dish.
Bake for 10 minutes.
Allow the crust to cool completely.
2. Make the Cream Cheese Layer
In a large mixing bowl, beat the softened cream cheese on medium-high speed for 1–1½ minutes until smooth.
Add the remaining ¾ cup sugar and vanilla extract.
Beat for another 1–1½ minutes until fully incorporated.
Gently fold in the whipped topping until smooth and fluffy.
Spread the mixture evenly over the cooled pretzel crust.
Be sure to spread the cream cheese mixture completely to the edges, creating a seal around the crust to prevent the gelatin from seeping through.
Refrigerate while preparing the topping.
3. Prepare the Pineapple Gelatin Layer
Drain one can of crushed pineapple and leave the second can undrained.
In a medium bowl, pour the boiling water over the pineapple gelatin mix.
Stir until completely dissolved.
Add both cans of crushed pineapple (one drained and one with juice).
Refrigerate for 15–20 minutes, stirring occasionally, until the mixture begins to thicken but is not fully set.
4. Assemble the Dessert
Carefully spoon the thickened pineapple gelatin mixture over the cream cheese layer.
Spread gently and evenly without disturbing the cream cheese layer.
Cover and refrigerate for at least 4 hours, or until fully set.
5. Serve
Cut into 12 squares (3 rows by 4 rows).
Garnish with whipped topping and pineapple chunks if desired.
Serve chilled.