Cut onion, carrot, cabbage, celery, and tomato into bite-sized pieces.
Heat olive oil in a pot and sauté onion and garlic.
Add the remaining vegetables and stir-fry for 2-3 minutes.
Pour in water and tomato sauce, then bring to a boil.
Season with bay leaf, salt, and pepper.
Simmer over medium-low heat for about 20 minutes until the vegetables are tender.
Serve the finished soup in a bowl.