Here is one of two Jello commercials that I have featuring Alice in Wonderland animation. This first one is pretty standard stuff, it re-uses feature film animation exclusively (with some new live action of a little girl with Jello), but re-rendered for TV with thick black lines for the crappy TV pictures in the 1950s. This originally came from a collection of commercials entitled Cartoons Celing Commercials. The jacket of this collection lists the date of these commercials as 1956, but I have no other corroborating evidence to support that date.
Voice over is by Sterling Holloway, which is pretty cool, and Alice's voice sounds like Kathryn Beaumont, but have not confirmed that.