Preheat oven to 400°F. Grease or parchment line a 9x13 baking dish.
Make the pretzel crust layer:
Stir together crushed pretzels, melted butter and 3 tablespoons granulated sugar. Mix well and press mixture into bottom of prepared 9x13-inch baking dish.
Bake 8-10 minutes, until set. Set aside to cool.
Make creamy middle layer:
While the pretzel crust is cooling, make the cream layer filling. In a large mixing bowl cream together cream cheese and white sugar. Fold in the stabilized whipped cream.
Spread mixture onto fully cooled crust. To avoid a soggy crust, just be sure the creamy layer reaches all edges of the pan. Set in refrigerator for at least 15 minutes.
Make the raspberry layer:
While the cream layer is chilling in the refrigerator, dissolve the raspberry Jello in boiling water. Allow cooling until the mixture is about the consistency of egg whites.
Stir in fresh raspberries and spread over the cream cheese layer. Refrigerate until set.
Notes
Stabilized whipped cream is basically homemade whipped cream where dissolved gelatin is added at the end to help it maintain its shape. You will get the best results (taste and texture) if you make and use the stabilized whipped cream, however, you have two other options:
Just use 1 1/2 cups heavy cream and whip it until firm peaks form. You can omit the gelatin if the pretzel salad will be eaten right away. If not, I highly recommend the stabilized whipped cream so that it will retain its shape and volume better.
Use Cool Whip instead of the stabilized whipped cream. This option is easy, however, these are the ingredients in Cool Whip: Water, hydrogenated vegetable oil (including coconut and palm oils), high fructose corn syrup, corn syrup, skimmed milk, light cream, less than 2% sodium caseinate (a milk derivative), natural and artificial flavor, xanthan and guar gums, polysorbate 60, sorbitan monostearate, and beta carotene.