Making yogurt comes up often; and I make enough in the microwave for my daughter and me to consume a half liter a day. So I have a CH saved reply:
I make 3.5 liters at a time in five 0.7 liter containers. All five fit in the MW at once. I start with two liters of whole milk, add 400 grams of whole milk powder and a TBSP of brown sugar, whisk very well, add a cup of yogurt from the last batch, add water to reach 3.5 liters, whisk a bit again, distribute in the five containers, place in the MW and zap on high for about three minutes and then for about a minute every hour and a half to two hours. Nothing exact, just keep it all warmer than body temp for 12 hours. The radiator will do the same job. Very thick and tart! No boiling.