In a large pot or a 4.5-quart Dutch oven, over medium heat, heat olive oil, enough to coat the bottom of the pot.
Add potatoes, carrots, and parsnips, stir periodically. Cook for about 7 minutes or until vegetables look slightly softened. Season with ½ tablespoon of salt.
Add celeriac root, celery, carrot tops, parsley and 8 cups of water.
Allow the liquid to come to a gentle simmer. Season with 1 tablespoon of salt and 1 teaspoon of pepper. Close the lid, partially. Lower the heat to low. Cook until the potatoes are fork-tender about 30 minutes. Remove and discard parsley, carrot tops and celery.
In the meantime, make hard-boiled eggs. Add eggs to a small pot, cover eggs with cool water and place on the stovetop over medium/ high heat. Cover the pot and let the water come to a rolling boil. Once the water reached this point, cook eggs for about 6 minutes. Turn off the heat, drain the water. Run the pot under cold water to stop the cooking process. Once the eggs have cooled down, dry and peel the shells.
Add spinach and scallions, and the remaining ½ tablespoon of salt. Squeeze juice from half a large lemon. Continue cooking for about 3 min. Turn off the heat and add sliced or diced eggs.
When serving, ladle soup into a bowl, add a spoonful of sour cream and a sprinkle of fresh dill.
Notes
*Use an egg maker to simplify hard boiling the eggs. *Use an egg slicer to cube the egg. Start with slicing the egg horizontally then gently rotate it, and slice it the other way. It will form cubes or strips.