Peel the potatoes and boil in salted water until al dente. Peel carrots and kohlrabi and cut into small slices.
Wash sugar snaps and cut in half lengthways. Boil carrots and kohlrabi until al dente, covered in a little water. Add sugar snaps about 3 minutes. Dice ham and fry in a little oil and remove. Heat the butter in the frying oil, stir in flour and fry. Douse with cream, soup and milk and simmer 5 minutes. Peel the eggs and add with the vegetables into the roux. Season with salt, pepper and lemon juice. Stir parsley into the sauce.
Arrange ragout with potatoes and sprinkle with chopped parsley and diced ham.