Cut the onion and grate the carrots. Put the water to boil, wash the nettle and then scald it. Drain the nettle and heat the oil in a saucepan. Put the onion and carrots to stew. Once softened, add the nettle with a little hot water. After 2 minutes, add hot water, enough to submerge the ingredients.
Simmer until the nettle stews. Add salt, black pepper, paprika and chopped garlic. Whisk the egg, flour and vinegar with a little cold water, remove the nettle from the heat and combine both mixtures. Return to the heat and stir the dish for a few minutes.
Take away from the heat once more and mix the crumbled feta cheese in. Serve the nettle with feta cheese dish slightly cooled.