To prepare the caramel, mix the water and sugar in a saucepan. Warm on medium heat. The sugar will start to caramelise after a few minutes of cooking. Watch the mixture carefully, especially when it starts to become darker. Turn off the heat as soon as the sugar starts to brown. Add the cream and mix well to get a smooth caramel. Place 1/2 teaspoon of creamy caramel in each bottle.
In a large bowl, mix the milk and the yogurt or starter sachet, and then whisk until you obtain a smooth mixture.
Pour the mixture into the bottles, over the caramel. Place them in the yogurt maker and cook in yogurt mode for 6 hours.
Once the programme is complete, close the bottles if you have not yet done so and place them in the refrigerator for at least 4 hours. Shake well before drinking.