In a medium bowl, combine the pretzels and ⅓ cup sugar. Pour the butter over top and stir to combine. Place the mixture in a 9x13-inch baking dish and press with a flat-bottomed glass or measuring cup to make an even layer.
Bake for 10 to 12 minutes until fragrant. Set on a wire rack for about 45 minutes to cool completely.
Once the crust is cool, place the cream cheese and ⅔ cup granulated sugar in a large mixing bowl. Beat on high speed with a hand mixer for about 2 minutes until very smooth. Scrape down the sides and bottom of the bowl as needed.
Fold in the thawed whipped topping. Spread the mixture into an even layer over the cooled crust. Refrigerate for 1 hour to set.
In a large bowl, combine the Jell-O and the boiling water. Whisk by hand for 1 to 2 minutes until the Jell-O is fully dissolved. Set aside to cool to room temperature for about 1 hour.
Meanwhile, hull the strawberries and slice them into ¼-inch thick pieces.
Once the cream cheese filling is set, carefully lay the strawberries over top of it, overlapping them slightly. Slowly pour the cooled Jell-O mixture over the strawberries. Refrigerate for 4 to 6 hours until the Jell-O is firmly set. Slice and serve.
Notes
How to crush pretzels: Place the pretzels in a sealed zip-top plastic bag and crush them by rolling with a rolling pin or by gently pounding with a mallet. Do not crush them into a powder. Instead, leave some pea-sized pieces to add texture to the crust. You can also pulse them in a food processor until coarsely chopped.
You can use a stand mixer to make the cream cheese filling. If you would prefer, use a stand mixer instead of a hand mixer. Beat the cream cheese and sugar on medium speed with a paddle or whisk attachment. Remove the bowl from the stand mixer and fold in the cool whip.
For clean, neat slices of strawberry pretzel salad, run a sharp knife under hot water and wipe it dry before slicing. Wipe off the knife between cuts and run it under hot water occasionally if slicing several pieces.