Put the milk, brown sugar (if you like it sweet), and the slit vanilla bean into a pot. Bring the mixture to a boil.

Remove the pot from the heat and strain the milk to remove the vanilla bean and any skin. Let the milk cool to about 50°C. You can use a thermometer or put a finger in: if you can hold it for about 5 seconds without burning yourself, the temperature is right.

Add 3 tablespoons of the cooled milk to the plain yogurt in a separate bowl and stir until smooth and no lumps remain. This tempers the yogurt.

Carefully pour the tempered yogurt-milk mixture into the remaining cooled milk and stir everything well.

Pour the yogurt-milk mixture into clean jars with lids. Place the jars on a baking sheet or in a casserole dish.

Cover the jars with a blanket and let them sit at room temperature for about 12 hours (or overnight). During this time, the milk will ferment into yogurt.

After fermentation, place a piece of kitchen paper on the surface of the yogurt in each jar to absorb excess liquid (whey). Leave the kitchen paper on the yogurt in the fridge for about 3 hours.

Remove the kitchen paper and the yogurt is ready to enjoy.

Serve your homemade yogurt plain or refine it as desired with fruit puree, fresh fruits, or granola.

You can save some of the homemade yogurt and use it again next time.

Enjoy!