In a large bowl, mix together the cake mix, butter, vanilla extract, eggs, chocolate chips, and butterscotch chips. Roll dough into 2-inch balls and place them onto the prepared baking sheets. Bake for 10 minutes in the preheated oven. Do not overbake; the cookies should be set, but still soft. Let cool on the baking sheet for a few minutes before removing to finish cooling on wire racks.