Slice the mini seedless watermelon in half.
Remove the watermelon from the inside! It’s a great idea to get one of these watermelon slicers! You don’t have to throw away the watermelon. Enjoy it as usual:) Using paper towels, dry off the inside of each watermelon half.
Prepare the two boxes of Jello mix according to the directions on the box in a large mixing bowl (you’ll need 4 cups of boiling water and 4 cups of cold water).
Pour the bowl of prepared Jello mixture into the hollowed-out watermelon halves.
Put the Jello-filled watermelon halves in the refrigerator. Place some paper towels underneath them just in case you spill any (I usually do!).
Let the Jello-filled watermelon sit in the refrigerator for 6 hours or until it is completely firm.
Remove the watermelon and slice it into pieces! NOTE: slice thick pieces! If the slices are too thin, the jello won’t stand up tall (it will flop over).