Peel the onion and chop finely. Rinse broccoli under running water, disassemble into small inflorescences, a stem, peel and cut into small cubes.
Heat the butter in a saucepan and fry the onion on it until transparent, add chopped broccoli to the onion and simmer together with the onion for 3-4 minutes with constant stirring.
Pour vegetables with vegetable broth, and if there is none, then just water, pour milk into a saucepan, bring to a boil, reduce heat and cook soup until tender for about 20 minutes. But after 3-4 minutes, remove a few broccoli inflorescences from the soup, they will be needed for serving. Season the soup with salt and pepper to taste and season with nutmeg.
While the soup is cooking in a separate saucepan, cook the tortellini according to the instructions on the package. Discard the finished tortellini in a colander, drain the water, transfer back to the pot and add a little butter to avoid clumping.
Season the finished soup with crème fraîche or sour cream and spice with a blender.
Pour the finished cream soup into plates, put the finished tortellini, broccoli inflorescences in a plate and sprinkle with finely chopped parsley and serve.