Wash the zucchini and use a large holed grater to shred the zucchini or if you have a slicer use that. ;Put zucchini shreds in a bowl, add salt and apple cider vinegar. Mix well and let it sit for 30 min. This is to get all the water out of the zucchini.;Squeeze out the water, by squashing the zucchini. ;Slice the onion julienne and heat up oil in a pot. Add the onion slices and stir. Slice white pepper and add it to the pot. Stir it and add water. Cook about 10 min, while still stiring. It shouldn't burn. ;Let the water evaporate and add ground paprika.;Add zucchini and cook all together for about 15-20 min and stir it. ;Add sour cream, salt, pepper and parsley. ;Let it simmer for 6-7 minutes. It should now be creamy. ;If it's not, you can add either 2 tsp flour in about 2 tbsp lukewarm water and stir it into zucchini casserole, let it simmer for 5 min or until thickens