Preheat the oven to 350°F and lightly spray an 9x13-inch baking dish with nonstick cooking spray.
In a medium bowl, combine the crushed pretzels, granulated sugar, and butter. Mix well. Pour the mixture into the prepared dish and press it evenly to form a crust. Bake for 15 minutes then allow to cool completely.
In a medium bow, use a mixer to beat the cream cheese until smooth. Add the powdered sugar and mix well. Fold in the thawed whipped topping. Once the crust has cool completely, spread the cream cheese mixture evenly over it. Chill in the refrigerator.
In a large bowl, whisk the gelatin mix with the boiling water until dissolved. Add the strawberries. (If using frozen berries, there's no need to thaw them.) Chill the mixture until it thickens to the consistence of egg whites, then pour over the cream cheese layer. Chill until set. Slice and and serve.