Preheat the oven to 350°F (175°C).
Crush the pretzels into small pieces, then mix them with melted butter and sugar.
Press the mixture into the bottom of a 9x13-inch baking dish to form the crust.
Bake the crust in the oven for about 10 minutes, then let it cool completely.
In a separate bowl, beat the cream cheese and sugar together until smooth and creamy.
Add the whipped topping and mix until well combined, then spread the filling evenly over the cooled pretzel crust.
Chill the dessert in the fridge while you prepare the Jell-O topping.
Dissolve the strawberry Jell-O (or your chosen flavor) in 2 cups of boiling water and stir until fully dissolved.
Let the Jell-O cool to room temperature, then pour it over the cream cheese layer.
Place the dessert back in the fridge for 2-3 hours or until the Jell-O layer is fully set.
Once set, slice into squares and serve with extra whipped cream or fresh fruit if desired.