Coarsely grate the sweet potatoes, potatoes, zucchini and carrots. Finely grate the onion. Mix in a bowl with oat flakes, breadcrumbs, eggs, parsley, salt, pepper and nutmeg.
Use a ladle or tablespoon to add about 3 small heaps to the pan with oil and carefully flatten. Fry the pancakes until golden brown.
For the side sauce, mix the sour cream with half a bunch of chopped dill, chives, salt and pepper and serve with the sweet potato and vegetable buffers. Decorate with dill if necessary.