Preheat the oven to 350°F. Grease a 9×13-inch baking dish.
Whisk sweet potato puree, evaporated milk, both sugars, cinnamon, nutmeg, ginger, salt, and vanilla until smooth.
Spread the sweet potato mixture evenly in the prepared pan.
Sprinkle the dry cake mix evenly over the filling. Do not stir.
Drizzle melted butter all over the surface, covering as much cake mix as possible.
Scatter pecans over the top for a crunchy finish.
Bake 45–55 minutes, until the top is deep golden and the edges are bubbling. Rest 15 minutes before serving.