Preheat the oven to 350°F.
Spread the strawberry pie filling evenly in the bottom of a 9x13-inch baking dish.
In a medium bowl, beat together the cream cheese, sour cream, powdered sugar, and vanilla extract until light and fluffy.
Dollop the cream cheese mixture evenly over the strawberry filling and spread gently to create an even layer.
Sprinkle the vanilla cake mix evenly over the cream cheese and strawberry layers.
Slice the cold butter into very thin pats and distribute them over the top of the cake mix to cover as much surface as possible.
Bake for 40 to 45 minutes, until the topping is golden brown and the filling is bubbling.
Serve warm or cooled, garnished with fresh strawberries if desired.