Wash and clean the spinach leaves, briefly blanch and drain thoroughly.
Peel and chop the onion, fry in the oil until translucent, add the chicken breast fillet and fry on both sides. Season with salt and pepper and deglaze with wine to taste.
Cook the tagliatelle in salted water.
Return the drained spinach leaves to the pan, add the crème fraiche, wine, salt and pepper and heat.