In a large stockpot, heat 1 tablespoon of olive oil over medium heat. Add the finely diced onion and sauté for about 5 minutes until softened and translucent.

Stir in the minced garlic and reduce the heat to low. Cook for an additional 2 minutes.

Add the diced carrots and celery to the pot, stirring to combine all ingredients. Fry them on medium-high heat for about 5 minutes.

Pour in 4 cups of vegetable stock, ensuring all vegetables are submerged. Increase the heat to bring the mixture to a gentle simmer, then reduce to medium-low. Cook for 5 minutes.

Once the vegetables are tender, carefully ladle the hot soup into bowls. Optionally, sprinkle finely chopped celery greens or parsley on top.