I didn't use Duncan Hines though, I used (dun dun dun!) Betty Crocker. >:O Reason being because my son loves Pineapple Upside Down Cake and Betty Crocker is free of his allergens, whereas Duncan Hines has the "may contain" warning. My son loves, Loves, LOVES pineapple upside down cake. So he was totally tickled by these, too. It's one to keep in our family recipe book!
Update 1/19/2014: The recipe link was no longer valid because it was removed from the Duncan Hines website. I found the following recipe on their site, but it was submitted by another user. I can't remember if this is the exact recipe I used, but glancing over it ...it looks to be very similar. I tweaked it a bit but I might have to make these again so nail down the recipe for sure (notice what I did there? Reason to make more!).