Wash and chop all your vegetables. Set them aside in a bowl, ready for cooking.
Heat the olive oil in a large pot over medium heat. Add the diced onion and sauté for 3-4 minutes until translucent. Add minced garlic and cook for another minute.
Add the diced carrots, celery, and potato. Stir and cook for 5-7 minutes until softened.
Add the frozen peas and corn, dried thyme, rosemary, salt, and black pepper. Mix well and cook for another 2 minutes.
In a small bowl, whisk together the flour and milk until smooth. Slowly pour this mixture into the pot while stirring. Then, pour in the vegetable broth and soy sauce. Bring to a gentle boil, then reduce heat and let it simmer for 15-20 minutes until vegetables are tender.
Taste and adjust seasoning if needed. Serve hot, garnished with fresh parsley.