The best part is that there's no icky stuff in it - no stabilizers, thickeners, sweeteners, or flavors.
All you need is:
4 cups soymilk
1 cup raw cashews
1/4 cup yogurt (from last batch, or any unsweetened plain non-dairy yogurt)*
* OR Vegan Yogurt Starter (available at Real Foods, Good Earth, and some Whole Foods in the refrigerated area)
Using a high speed blender, pulverize cashews and 3 cups of soy milk. Strain through a mesh sieve to catch any hard nut chunks that survive into a medium saucepan. Add last cup of soy milk. Place a thermometer in pan, and heat until 110 degrees F. (Hotter than that might kill the culturing bacteria, and you don't want that!)
Whisk in yogurt or starter. Pour mixture into prepared glass containers in a crockpot (lined with a kitchen towel) and leave on "WARM" setting for a minimum of four hours (I've had it take up to eight hours) until the yogurt is thick and tastes tangy. Allow to cool to room temperature and cover, then refrigerate.
Here's the picture tutorial, for the visual learners like me: