Source: Tibetan Cooking by E E Kelly
1/2 gallon organic whole milk
1/4 cup Fage yogurt
Pour milk into large pot; cover. Bring to just below boiling on low heat (3.5-4 minutes)
Turn off milk and allow to cool (about 45 minutes). Cooled milk should be warmer than body temp but not burning (110F)
Take out 1 cup scalded milk, mix with half the yogurt. Add this mixture into the pot. Stir well (whisk)
Cover pot with lid. Wrap pot with thick towel to retain heat. Leave pot in oven overnight (oven is off).