I like to use a graham cracker crust, but you could use any type -- pastry, oreo cookie, 'Nilla wafer, whatever. The filling is made as follows:
Put 1½ cups of milk (whole is best, but at least 2% fat -- nonfat won't thicken) in a medium saucepan over low heat, until bubbles form around the edge. A low heat will keep the milk from burning as it heats, so be careful with the temperature!
Whilst that is happening, mix together:
- 3T (that's Tablespoon) cornstarch
- 4T sugar
- ¼t (teaspoon) salt
- 5T unsweetened cocoa (or less, if you're afraid of real chocolate taste)
After the dry ingredients are mixed, add ½cup of milk and whisk until blended.
Add this mixture to the scalded milk, and turn up the heat to medium. Whisk the mixture until it reaches a boil, then boil for one minute (whisking constantly, so it doesn't burn on the bottom).
Remove from heat, let cool to lukewarm and add 2t vanilla extract.
Chill and serve.