Think it might have been Noise that posted this originally but I saved it for a messy day.
"Pudding is made of corn starch [corn flour]. It's easy to make a pudding-esque substance by mixing cornstarch and cold water until you have a thick batter. Slowly pour that into boiling water and continue to boil for awhile, stirring constantly. 5 minutes will get you a white-ish goo. After about 10 minutes, it will get very translucent - almost clear.
Experiment with the amounts. 1 cup cornstarch to a gallon of water is a good starting point. Remember that it will thicken a LOT as it approaches room temperature and almost solidify in the refrigerator. If you want *real* pudding (i.e. edible) replace some of the water with milk and add some sugar & vanilla. To make it chocolate, I think you could probably add Hershey's syrup or maybe powdered cocoa. You can also use food coloring, paint, etc."
The big difference it the use of corn flour. When I used normal flour in the past I was picking lumps of the stuff out of my pubes for days.
On a related matter, how is powdered custard versus a carton of the ready made stuff? Tara, I think you are the expert on this one.
Smudge
-- Smudge