Heat olive oil in a large pot over medium heat. Add chopped onion and sauté until translucent, about 5 minutes.

Add minced garlic and cook for another minute until fragrant.

Stir in the canned diced tomatoes (with juices), vegetable broth, dried basil, dried oregano, salt, and black pepper.

Bring the mixture to a boil, then reduce heat and let it simmer for 20 minutes.

Using a blender, carefully blend the soup until smooth. You may need to do this in batches.

Return the blended soup to the pot and heat through.

Ladle the soup into bowls and top with crumbled feta cheese and chopped fresh basil.