You need an Instant Pot. There is a "Yogurt" button.
Ingredients: Milk (any milk works); Plain yogurt for grocery stores.
Steps:
1, Clean the pot. Add a cup of plain water and pressure cook for 1 minute. Release the pressure and dump the water. This is to thoroughly remove whatever bacteria.
2, Add milk. Press the Yogurt button a couple times until you see it shows "boil".
3, Cool down the milk until it's at a temperature good for drink directly.
4, Mix a couple spoonfuls of plain yogurt with the milk in a bowl. Add it to the pot.
5, Press the Yogurt button and set the time to 12 hours.
6, Refrigerate the yogurt for a few hours.
That's it!