Fill a large bowl with cold water. Add vinegar and 2 tablespoons of flour and mix. Brush black salsifies vigorously under cold running water, peel and immediately place in the prepared flour vinegar water
Bring salted water to the boil in a wide saucepan. Add black salsifies, cover and cook for about 15 minutes until firm to the bite. Take out and rinse with cold water
Wash thyme, dab dry, remove leaves and chop finely. Whisk eggs. Season with salt and pepper. Stir in thyme. Peel onion, halve and chop finely. Cut sausage into slices and halve. Grease a pan (approx. 18 cm Ø) with oil and heat up. Fry half the chorizo and half the onion in it for about 4 minutes while turning them until crispy. In the meantime, cut the black salsifies in half lengthwise. Place half of the black salsifies in a star shape in the pan and pour half of the whisked eggs over them. Cover and allow to set on low heat for approx. 15 minutes. Bake another omelette in the same way