In the 1950's, Jell-O and Dole Pineapple joined forces to create the Jell-O in the Pineapple Can recipe.
Open the can and pour off the pineapple juice but leave the pineapple in the can.
Dissolve the Jell-O in boiling water and permit it to cool slightly before pouring the Jell-O and water mixture into the can, over the pineapple. If desired, place the banana or other fruit in the center of the rings of pineapple.
Chill until set.
To serve, run a knife around the inside of the can and tip it out. (Before rimmed flip-top cans, one pushed the jelled mixture through and out, using the bottom of the can.)
Slice between the pineapple rings and serve.
*Be careful if using a pull-top can because the can's lip won't allow the Jell-O and pineapple to slip out as smoothly as from cans which can only be opened with can openers.