Peel onions and garlic. Chop the onions finely, chop the garlic. Heat butter in a saucepan, sauté onions and garlic, add spinach, sultanas and 100 ml water. Bring to the boil covered and steam for 5-10 minutes, stirring occasionally.
Roast pine nuts in a pan without fat while turning, remove immediately and let cool. Season spinach with salt, pepper and nutmeg.
Bring 1 litre of water to the boil briefly. Add the noodles to the hot, no longer bubbling water and leave to stand for a maximum of 4 minutes. Pour the noodles onto a sieve, drain and fold into the spinach.
Arrange lentil noodles with spinach in 4 deep bowls. Crumble the feta, spread on top and sprinkle with pine nuts and pepper.