Place diced potatoes into a medium pot and cover with water. Add 1 Tbsp vinegar and bring to a boil, continue boiling for 10 minutes or until the potatoes are just cooked.
Drain potatoes and carefully rinse with cold water to cool down.
In the meantime, boil the eggs and cool them in ice cold water.
On a cutting board dice the 2 whole eggs and 2 egg whites (set 2 yolks aside), cucumbers, radishes and ham. Chop the dill and green onions and place everything in a large pot.
In a separate large bowl, whisk together sour cream and remaining 2 egg yolks until combined, add the 8 cups of boiled cooled water, remaining 2½ Tbsp of vinegar and 2½ tsp of salt, whisk gently until combined. Pour the mixture into the pot over the rest of the ingredients. Gently stir to combine.
Let the veggies soak all the flavors for 2-3 hours before serving.
The soup must be kept if the refrigerator and served cold.
This is the type of soup that gets better and better the second day!
