Heat the oil in a large pot, add the veggies (celery, garlic, onion and red bell pepper) and cook over medium-high heat for 5 minutes or until golden brown, stirring occasionally. If you don't eat oil, just use some vegetable stock or water instead.
Add all the remaining ingredients, stir and bring to a boil. Then simmer for 10 to 15 minutes. Once the soup is ready, remove and discard the bay leaves.
To thicken the soup, use an immersion blender and do 3-4 quick pulses. You could also transfer 1 cup (250 ml) of the soup to a regular blender and blend, then transfer back into the pot. This step is totally optional.
Serve immediately with your favorite toppings (I added tortilla chips, diced avocado and chopped cilantro) or keep leftovers in an airtight container in the fridge for 5-7 days.
Notes
Nutritional info has been calculated by using 1 tablespoon of extra virgin olive oil and water. It doesn't include the toppings either.