01 - Preheat oven to 375°F for the croutons.
02 - Toss bread cubes with olive oil, salt, and garlic powder (if using). Spread on a baking sheet and bake for 10-12 minutes, stirring once, until golden and crisp. Set aside.
03 - In a large saucepan, heat olive oil over medium heat. Add onion and sauté 5-6 minutes, until soft and translucent.
04 - Add garlic and cook for 1 minute, stirring often.
05 - Stir in tomato paste, cook for 1 minute, then add canned tomatoes (with juice), breaking them up with a spoon.
06 - Pour in vegetable broth, add sugar, salt, pepper, and oregano. Bring to a simmer.
07 - Simmer uncovered for 20 minutes, stirring occasionally.
08 - Add fresh basil leaves and blend the soup until smooth using an immersion blender (or in batches in a blender; return to pot).
09 - Stir in heavy cream and heat gently until warmed through. Taste and adjust seasoning.
10 - Ladle soup into bowls, garnish with extra basil leaves, and scatter croutons on top. Serve immediately.