Peel the vegetables and cut them into cubes. Finely chop the kohlrabi leaves and set aside.
Sweat the onion and garlic in the heated oil. Add the carrots, kohlrabi and potatoes, sauté briefly and then deglaze with the stock. Add the bay leaf and cook the vegetables for about 15 minutes. Mix in the corn kernels and heat. Season the soup with salt, pepper and paprika powder, then serve sprinkled with chopped parsley and the tender kohlrabi leaves.