Preheat oven to 400ºMix together the crushed pretzels, chopped pecans, melted butter and the 3 tablespoons of sugar. Press mixture evenly into bottom of 9" by 13" baking dish and bake for 8 minutes. Set aside to cool on rack.
Make the whipped cream.
In large bowl, combine whipping cream, sugar and vanilla. Beat with hand held mixer until medium-stiff peaks form. Set aside.
Make cream cheese filling.
In another mixing bowl, beat together cream cheese and ¾ cup sugar until well combined. Fold in the whipped cream with a spatula or wooden spoon until mixed well and smooth. (Alternately, you can use your mixer on low speed.)
Spread the cream cheese filling evenly over the cooled crust. Be sure to spread to all sides and corners to seal completely. Chill in the refrigerator for 1 to 2 hours.
In medium bowl, dissolve gelatin thoroughly in boiling water. Allow to cool slightly and then stir in the thawed strawberries and can of crushed pineapple.
Carefully pour strawberry mixture over chilled cream cheese mixture. Cover tightly with plastic wrap and chill until set, preferably overnight.
To serve, cut into squares or slices and top with a dollop of whipped cream.
Notes
I used small pretzel twists and crushed them in a Ziploc bag with a rolling pin.
Be sure to spread the cream cheese mixture evenly all over the baked crust, sides and corners, every nook and cranny. This prevents the gelatin from seeping down into the crust and possibly making it soggy. You want that crisp salty crust!
Do not drain the frozen strawberries or crushed pineapple.
You can use one container of frozen whipped topping instead of the homemade real whipped cream. (I think that's an 8-ounce container of Cool Whip.)
Chill time varies but I find overnight is best for the dessert to set properly.