Melt oil and butter together over medium heat in a large pot with a tight fitting lid. Add popcorn and sprinkle sugar evenly over kernels. Place the lid on the pot and turn heat to medium-high. When popcorn begins to pop, using potholders, shake pot every 20 seconds to reduce risk of burning the sugar. Once popping slows, remove from heat and remove lid carefully. Sprinkle with salt and add to a large bowl.

Melt candy melts. Stir in cake mix. Pour over popcorn. Add toasted pecans and stir until all the candy is incorporated. Turn out onto a baking sheet covered with wax paper and chill until candy hardens. Store in a sealed container.