Method 1: Add the skim milk powder ot the yogurt as well as the sugar. Leave to drain in the refrigerator and it's done.
Method 2: Drain the plain yogurt overnight in the refrigerator.
When the yogurt has decreased to half its original volume, take it out, and mix in enough skim milk powder so that the cream has a subtle sweetness and is no longer sour.
Optionally, add some finely chopped cheese.
Add sweetener to taste. If you add sugar to yogurt after it's been drained it will become more watery, so I think it's best to just sprinkle it on.
Serve with cornbread.
Even if you use 100% soy milk yogurt, if it's made with sweetened soy milk it won't taste bean-like, at all but actually quite delicious.