as posted by Debbie F. in the October 2004 What's for Dinner? thread.
Kitty Litter Cake
2 cakes--one white and one chocolate, baked ahead & cooled
1 large Instant Vanilla pudding, made according to directions
Large bag of vanilla sandwich cookies, smashed into fine crumbs
Several tootsie roll candies
Divide cookie crumbs into 2 batches. Crumble cakes into fine crumbs. Add 1 batch of cookie crumbs. Add just enough pudding to make moist, but not too wet. Zap 3 tootsie rolls for 10 seconds in the microwave. Use hands to roll them into the shape of, well, you know, kitty discards.
Dribble with 2nd batch of cookie crumbs and put down more tootsie rolls. You can even add a little green food coloring to 1/4 cup of the cookie crumbs (to resemble chlorophyll) and place the clumps on top. I draped some of the tootsie rolls onto the edge of the pan.
Serve in a clean litter box, and use a "pooper scooper" to dish it out. I got a small litter box at Walmart for about $2.00, and a scooper for .82 cents. Well worth the investment, as all I got were "Gross!" from everybody!!