Wash the chicken, vegetables and herbs for serving, and dry with paper towels. Cut the chicken fillet into small pieces. Scald the tomatoes with boiling water, remove the skin, grate the pulp or chop with a blender. Separate the cauliflower into florets. Peel the onions and garlic and chop finely. Separate the parsley leaves from the stems.
Start cooking the chicken and vegetables. Heat vegetable oil in a thick-bottomed saucepan and fry the onion over medium heat for 4-5 minutes. Add the fillet pieces and cook, stirring, for another 5 minutes. Then add the cauliflower florets and fry, stirring occasionally, for 3-4 minutes.
Prepare vegetable stew. Add tomato puree to the chicken and vegetables and bring to a boil. Add a little water or broth if necessary. Reduce burner power and simmer with the lid closed for 15-20 minutes. Add chopped garlic, season with salt, pepper, sugar, stir. Simmer for another 5 minutes.
Place the chicken fillet with vegetables on serving plates and garnish with fresh parsley leaves.