1, main ingredients: 500g milk, 50g plain yogurt, tools: 1 sealed fresh-keeping box, 1 spoon, 1 rice cooker, and auxiliary materials: boiled water and clear water.

2. Wash the crisper+lid and spoon and scald it with boiling water.

3. Add water to the rice cooker and heat it until the wall of the cooker is slightly hot. Pour 500g milk into the fresh-keeping box, sit in the hot water of the rice cooker, cover the lid and heat the milk to warm.

4. Take the fresh-keeping box with milk out of the rice cooker, cover it again, and add 50g yogurt to the milk.

5. Stir the milk and yogurt evenly with a small spoon.

6. Cover the crisper.

7. Put the fresh-keeping box into the rice cooker, cover the lid, turn off the power supply and ferment for 12 hours.