Preheat the oven to 350°F (175°C).
In a medium bowl, combine crushed pretzels, melted butter, and granulated sugar until evenly mixed.
Press the pretzel mixture firmly into the bottom of a 9x13-inch baking dish to create an even crust layer.
Bake the crust for 10 minutes, then remove it from the oven and allow it to cool completely.
In a large mixing bowl, beat the softened cream cheese until smooth and creamy.
Add granulated sugar and vanilla extract, then continue mixing until fully combined.
Fold in the whipped topping gently until light and fluffy.
Spread the cream cheese mixture evenly over the cooled pretzel crust, making sure to spread it completely to the edges of the dish to help seal the layer.
In another bowl, dissolve the strawberry gelatin in boiling water and stir until completely dissolved.
Allow the gelatin mixture to cool slightly to room temperature.
Stir the sliced strawberries into the cooled gelatin mixture.
Carefully pour the strawberry gelatin mixture over the cream cheese layer.
Refrigerate the dessert for at least 4–6 hours, or until fully set and chilled.
Slice into squares and serve cold for the best flavor and texture.