Wash the cubed potatoes in warm water until all of the starch is removed. This is a very important step.
Place into a saucepan, cover with boiling water, add two crushed vegetable stock cubes and bring to the boil.
Once boiling cover with a lid and reduce the heat to a simmer for 15 - 20 minutes. You should be able to push a fork easily into the potatoes.
Drain the potatoes, retain a few tablespoons of the stock. Allow the potatoes to sit and cool for a few minutes.
Mash the potatoes with the masher for a minute or two. Ensuring you do this evenly removing lumps. Once you have finished mashing, mash some more. You can never mash too much.
Now grab your fork, add the stock and you want to "whip/beat" the potatoes with the fork. Fast whipping in circular motions. Do this for 30 seconds and then add a large pinch of salt. Whip some more.
Slowly stir in the quark and yoghurt. Taste.. you may a little more salt.
Add more quark or yoghurt if needed. Serve and enjoy