Peel the onions, cut into cubes and fry in butter until golden. Add the mushrooms and fry for another 2 minutes. Deglaze with white wine. Add the peeled and diced potatoes and carrots and sauté over medium heat for 10 minutes. Add the tomatoes and continue to simmer. After 5 minutes add water. Also add the curry and paprika powder and mix well. In the meantime, peel and cut the celery root, add and zucchini cut into pieces. Simmer for 20 minutes over low heat. Season to taste with salt and pepper.