Put the milk warm with vanilla extract and boil. Lower the heat, add the sugar and let it dissolve. Preheat oven to 40-50 ° C.
Once cooled milk (40-50 ° C), add milk powder and yogurt and mix. You can put food coloring. Fill the pots of yogurt and cover tightly.
Put the pots in a bain-husband in a baking dish (with water). Bake 15-20 minutes, turn off the oven and do not open it. Attention to time and temperature: 50 ° C and 20 min = + strong and acids
Let stand the equivalent of one night in the closed oven. Get out your yogurt. Place in the fridge (to keep), where they will gain strength.