Instant Pudding
Source:  Make Ahead Cooking and Mixes at Recipelink.com, provided by Karen Farr, The Food Allergy Kitchen, Yahoo Group  

Instant puddings have as one of their ingredients pre-gelatinised starch which makes them an "add milk and sitr" commodity.

Gelatinized starch is a pre-cooked starch that is used as a thickener. After cooking the liquid mixture of starch, fluid and additives it is dried into a powder. When a liquid is added to this pre-gelatinized starch, as in an instant pudding mix, it re-forms into the thickened consistency of a cooked starch.

Pre-gelatinised/pre-gelatinized/gelatinised/gelatinised starches (eg corn, wheat, maize, potato) are usually found commercially. If you can find a source, you would then have to find and adapt a commecial recipe or adapt one of you own.

Versatile Pudding Mix 

5 quarts instant nonfat dry milk powder or dairy free substitute

 3½ cups sugar

1¾ cups cornstarch    

2¼ teaspoons salt

Additional Ingredients for Vanilla Pudding: 2 cups water, 1 whole egg
yolk -- lightly beaten, 2 teaspoons vanilla extract.

Additional Ingredients for Chocolate Pudding:

¼ cup baking cocoa

2 cups water

1 whole egg yolk -- lightly beaten

2 teaspoons vanilla extract

In large bowl, whisk together the first 4 ingredients. Store in an airtight container or resealable plastic bag for up to 1 year. Yield: about 10 batches (21 cups total)

To prepare VANILLA PUDDING: -- In a saucepan, combine 2 cups pudding
mix and water. Bring to a boil over medium heat, stirring constantly. Remove from the heat. Gradually stir about 1 cup hot mixture into egg yolk; return all to the pan. Bring to a gentle boil; cook and stir for 2 minutes. Remove from the heat; stir in vanilla. Pour into dessert dishes. Refrigerate.

Yield: 6 servings per batch