@emily you start with a yoghurt that has live cultures - I used a soy one from the supermarket.

2/3 cup of cashews, soaked
1 litre soy milk
1/2 cup yoghurt

You also need a food safe thermometer, a saucepan, and clean jars.

1. Blend the cashews with the soy milk until super smooth (mine is still a little grainy, tbh)
2. Warm the soy and cashew mixture until it's 40°
3. Take off he beat and whisk in the yoghurt.
4. Pour the mixture into jars, out the lids on, and let it sit for 4-8 hours in a warm place. When it's aour and thick, put it in the fridge.

Mine doesn't get super thick, but it does get lovely and sour, and it keeps for weeks in the fridge. You can thicken it with gums or tapioca, but I don't love that texture.

I can't get a warm enough spot here most days, so I use small jars instead of one big one, and sit them in a heated water bath either on the atover so I can turn it on to heat it up as needed, or in the oven. It needs to stay between 30° and 40°. If the mixture gets hitter then 40ish it kills the bacteria, if it gets too cold before it's done, it doesn't thicken.