Chop the potatoes into large chunks
Boil the potatoes in a saucepan for about 20 minutes until soft
Drain the potatoes and empty into a bowl. Set aside.
In the same saucepan, over a very low heat, melt the butter and add the onion and garlic powders, stirring until they are incorporated into the butter, about 30 seconds.
Remove the saucepan from heat and rice the potatoes directly into the pan with the melted butter (if you don't have a ricer, you can mash them in, but promise me you will at least consider buying a cheap potato ricer!!)
Mix the potatoes and butter together
Add some salt and pepper if you wish
Put the pan back on low heat, and add the yogurt and cheese to the saucepan. Stir quickly, until the yogurt is mixed through and the cheese has melted, and the potato will start to come away from the sides of the pan a little more easily
Serve it, love it!