Heat the milk in the dutch oven to 200F, stirring to make sure it doesn't burn
Turn the heat off, cover, and let sit until the milk reaches 115F
Take a cup of milk out, whisk into the yogurt, and return the mixture to your milk. Whisk to combine.
Cover, wrap with a couple of layers of dishtowels, and keep in a warm (not hot) place overnight
Once it's set, strain through cheesecloth into a bowl in the fridge. This may take several hours depending on the fineness of the cloth.
Whisk or beat until smooth and creamy.