If you like yogurt and buy it often, you are going to like this recipe, which will teach you how you can quite easily make your own yogurt. You can eat it plain, or can add fruit preserves or just simply fresh fruit. For vanilla yogurt you need to add 1 oz (25 g) sugar per container (roughly) and a few drops of vanilla essence.
You will need a small 4 oz (100g) container of plain yogurt (from any company) to get started. I use greek yogurt. Make sure it does not have any other ingredients in it apart from milk and active yogurt culture. You will also need plastic containers with lids - you can just reuse the ones from store-bought yogurt, as I do; a microwave safe tall dish, 1 gallon of the milk of your choice (1%, 2%, full fat or fat free). I use 2% and full fat since I use yogurt as desert, and as a substitute for sour cream in many recipes.
To start, pour the milk in the glass bowl almost all the way up, leaving 1 inch of space at the top. Set the microwave oven to high for 25-27 minutes. This time could be shorter, or slightly longer, depending on the model of your microwave oven. The one I use is 800 Watts. The most important thing is to see when the milk starts boiling, and from that point it needs to continue boiling for 4-5 minutes (it should look like in the picture).
Here is how the finished product should look: