Place the pretzels in a resealable bag and use a rolling pin to crush them into small pieces, not a fine crumb.
In a small bowl mix the crushed pretzels, 1/4 cup of granulated sugar, and the melted butter. Spread the mixture evenly into a 9×13 pan. Bake for 10 minutes, and remove the baking dish to a wire rack to cool completely.
After the crust has cooled completely, use an electric mixer to beat the cream cheese, 1/2 cup sugar, and vanilla extract together until light and fluffy. Gently fold in the whipped topping (Cool Whip) until smooth and combined. You should not see any cream cheese streaks.
Spread the cream cheese mixture all the way to the edges of the pretzel layer, sealing the edges. A tight seal will prevent the jello from seeping through. Refrigerate for 1 hour to set.
While the cream layer is setting up in the fridge, in a large bowl or measuring cup mix the boiling water with the jello, and set it aside to cool to room temperature.
Once the cream cheese layer has set up spread the sliced strawberries evenly over the top. Or you can stir the strawberries into the jello liquid.
Gently pour the jello over the strawberries.
Cover and refrigerate for at least 4-6 hours up to overnight.
Notes
You may also use frozen strawberries. Be sure to thaw and drain them well.