Saute onions and garlic until light brown in large pot

Pour in chopped butternut, carrots and potatoes and saute with spices and salt

Begin to add water as it cooks

Leave to boil until all ingredients are very soft and fall apart when you press them with a spoon.

Add more water if necessary

Let it cool and pour in blender. Blend until smooth

Return to pot and cook again, this time adding yogurt, vinegar and grated cheese.

Add more water or yogurt according to your preference of consistency

Serve while hot.