Yogurt is a greatly consumed food in our home. When we shop, we always check to see if there is any yogurt for half off and go to the checkout with at least a coupon or two. It is my 2yoDD's favorite food.
In my pre-kids days, I used to often make it. Then I had a batch fail and didn't bother anymore. I don't know why. Yogurt is sooo simple to make! I got the recipe I use from a church cookbook we got as a wedding gift. I have a batch in the oven right now and it too no time to prepare. Here we go:
4 cups water
2.5 cups powdered skim milk
1/2 cup plain yogurt to use as starter (gelatin free, check ingredients)
Whisk water and milk powder together in a large saucepan. Heat on medium until warm **Not Hot**. Put yogurt starter in a glass bowl. Add the warm milk and gently stir together. Cover and put in the oven over night or 8-10 hours with the light on (if your light doesn't work like mine, I put it in the oven about half an hour after making bread when it's still kind of warm but not too hot). Makes 4-6 cups.
This usually makes a nice thick yogurt. If it is very runny or looks like mucus, it either didn't set right, it was too warm or the starter wasn't good. I haven't figured out what bad results come with things gone wrong.
You can use yogurt that has been frozen if you want to keep some starter on hand. I usually use Astro Balkan Style natural yogurt or Western Plain yogurt as both only contain milk ingredients and bacterial culture.
Youc an add lots of yummy things to yogurt or just enjoy it plain. You can use it as a sub for sour cream or you can drain it through a cheese cloth for yo-cheese (almost like cream cheese and can take it's place).
Edit to add: Before going to bed, I checked the yogurt after having it in the oven on a warm temp most of the day and it hasn't formed yet so I added a little more starter yogurt and put it in the oven for overnight. Hopefully it's "done" in the morning or I may just use it for sour cream or maybe make frozen treats with it. It certainly won't go to waste!
Edited again to add: By morning this came out perfectly. DD declared she loved it with some jam added to it and DH seems to like it :)