Peel the tomatoes first and chop them into small pieces. Peel the potato as well, and chop it into small pieces.
Add the flour and olive oil in a saucepan on medium heat and cook for a few seconds, then add the chopped tomatoes and potatoes.
Mix well and add the water, cook for about 10 minutes on low heat. Then add the salt, black pepper and garlic and simmer for another 15-20 minutes (make sure the potatoes are completely soft).
Finally, decorate with fresh basil leaves and enjoy. (If you want a thick and uniform mixture, you can use a blender and blend the whole soup well.)