Heat oven to 350°F. Lightly grease a 9×13-inch baking dish.
Combine crushed pretzels, melted butter, and granulated sugar until evenly moistened.
Press mixture firmly into the dish. Bake 10 minutes, then cool completely on a rack.
Beat cream cheese with powdered sugar until smooth and fluffy.
Fold in whipped topping. Spread over cooled crust, sealing tightly to the edges. Chill 15 minutes.
Dissolve strawberry gelatin in boiling water, stirring until clear. Stir in cold water and chill until slightly thickened.
Stir sliced strawberries into the syrupy gelatin. Spoon gently over the cream layer and smooth the top.
Refrigerate until fully set, about 4 hours. Slice into squares and serve chilled.