1. Preheat oven to 350°F (175°C). Grease a 9x13-inch baking dish with butter or non-stick spray.
2. In a large bowl, whisk together melted butter, eggs, brown sugar, corn syrup, vanilla bean paste, and salt until smooth.
3. Pour the mixture into the prepared baking dish.
4. Sprinkle the reserved 1/4 cup of cake mix evenly over the top.
5. Scatter chopped pecans over the top.
6. Sprinkle the remaining cake mix evenly over everything.
7. Drizzle 2-3 tablespoons of melted butter over the cake mix.
8. Arrange whole pecans decoratively on top, if desired.
9. Bake for 45-55 minutes, rotating halfway through, until edges are golden and center is puffed with a slight jiggle.
10. Let cool at room temperature for 30-45 minutes before slicing.