We decided to have a Rainbow-themed birthday party for Stella's 5th birthday and I found this Jell-O idea on Pinterest. There are many different versions of how to do this - some even have a beautiful Cool Whip layer between each color. And this would also be fun on St. Patrick's Day. Many thanks to Do Better and her instructions found HERE.
What I did...
6 oz. boxes of Red, Yellow, Blue, Purple Jell-O
Box of Knox Gelatin (contains 4 envelopes, is right next to Jell-O)
In a bowl, mix box of purple Jell-O with one envelope of Knox Gelatin. Add 2 cups of boiling water and dissolve Jell-O. Add 1/2 cup of ice. Stir until it thickens. Pour into a 9x13 pan (I greased mine, but not sure you have to). Put in the refrigerator and leave it alone until really firm. I'd wait at least an hour.
Repeat steps with blue, yellow and red. Pouring your cooled layer over top of the already firm layer. After completely cooled, cut into squares to serve.
Orange and Green are NOT needed. When stacked, the blue and yellow will create the green. I did NOT use green and just look at the photos...it works! I will admit I did use orange because I had room in the pan and I wasn't sure if it really would create the "missing" colors...but the GREEN proves it does!
This is an EASY process, but you have to take into account the time it will take each layer to become firm. For our Saturday party I actually started the process on Thursday night with the purple layer. The blue layer was Friday before work and Yellow and Red were Friday night. I cut them Saturday morning.
Enjoy! These were gobbled up quickly and talked about most of the afternoon.