Warm the coconut milk on medium heat until it comes to a gentle simmer. The idea is to warm the milk and not boil it. Take it off the heat and let it cool down to room temperature.
Pour the warmed then cooled coconut milk into the container you want the yogurt to set in. Add the regular full fat yogurt to it and mix well using a spoon. Cover the container with a muslin cloth and hold it in place using a rubber band, and leave it set on the countertop overnight. Note: In warm climates and during the summer this works, but if you live in a cooler climate you might need to find a warm spot for the yogurt to set in. Try the inside of the oven (with the light on but the heat off).
Once the yogurt has set on your countertop for at least 8 hours, transfer the container to the fridge for another 6-8 hours to allow it to chill and completely firm up. If you want it further thickened (like Greek yogurt), you can transfer the yogurt to a strainer lined with a cheesecloth, set over a container to catch the excess water, and leave it to drain in the fridge for another few hours.
Coconut yogurt is naturally tangy, and if you enjoy the taste as it is, skip the sweetener. If you prefer something slightly sweetened, add in some agave or maple syrup to taste. Store in the refrigerator, and consume within a couple of days.
*Note:
If you have some separation after the yogurt has set, it’s ok - just stir it in or scoop off the top layer.
Coconut yogurt is tangy, but if tastes extremely sour to you or smells weird, something has probably gone wrong.
Recipe by Sprig & Vine at http://sprigandvine.in/coconut-yogurt/