Pat the chicken breast dry with paper towel and cut into bite-sized pieces. Heat the oil in a pan, fry the onions for 2-3 minutes, then add the chicken. Cook the chicken for five minutes, until golden brown. Then add the mushrooms and fry them. Now add the chicken broth and tomato paste, season with salt and pepper and let everything simmer for 10 minutes.
Bring 500 ml of salted water or vegetable stock to a boil in a large pan. Add the cauliflower and broccoli and cook them together for 10 minutes until the vegetables are soft. Then set the saucepan aside and pour off the excess water. Add the butter, a little salt and pepper and mix the vegetables in the food processor or with the mixer to puree. Now mix in the chopped green onions.
Serve the puree with the chicken goulash and garnish with a little parsley.