For the meatballs, peel, wash and cut the sweet potatoes and potatoes into smaller pieces. Cover the potatoes and cook them in salted water for about 25 minutes. Cook the sweet potatoes for about 15 minutes. Drain and let it evaporate.
Then mash roughly with a potato masher. Let it cool down.
Peel the red onion and cut into thin rings. Fry in 1 tbsp. hot oil. Wash parsley, shake dry and chop finely. Crumble feta coarsely. Stir onion rings, parsley, feta and egg into the mashed potatoes.
Form about 8 flat meatballs from the mixture.
For the spinach, peel onion and garlic. Dice onion finely, chop garlic finely. Heat 1 tablespoon of oil in a pot, fry onion and garlic. Add the frozen spinach, pour 6-7 tbsp. water, bring to the boil and simmer covered for about 15 minutes.
Spread the flour on a plate and turn the meatballs in it. Heat 4 tablespoons of oil in a large frying pan. Fry the meatballs for 4-5 minutes on each side until golden brown. Stir the crème fraîche into the spinach, season with salt, pepper and nutmeg.
Arrange the meatballs with spinach.