Braise slightly the cleaned and thinly sliced onion rings on zweigelt grapeseed oil.
Add the peeled potatoes and carrots cut into cubes, and pour on water.
Toss in the rosemary twig, add salt and pepper and then cook it all soft.
When the veggies are soft, take out the rosemary twig and mash the soup with a hand mixer.
To season, mix the plain yogurt with the hazelnut oil and pour it on top of the soup.