Prepare pan: Preheat oven to 350°F and grease a 9- in. x 13-in. baking dish with cooking spray or butter.
Add pie filling to pan: Dump the strawberry pie filling into the baking dish and spread it into an even layer.
Sprinkle cake mix over filling: Scatter the dry cake mix evenly over the top of the pie filling. Make sure the pie filling is completely covered.
Add butter: Place pieces of butter over the top of the yellow cake mix, making sure the butter covers the cake mix as evenly as possible.
Bake cake: Bake for about 50 to 60 minutes or until the top of the cake is golden and the filling is bubbly.
