In a spacious pot, warm the olive oil over medium heat. Once hot, add the chopped onion and sauté for about 5 minutes, or until they turn soft and translucent, stirring occasionally.
Incorporate the minced garlic into the pot and sauté for an additional 1-2 minutes until fragrant, being careful not to let it burn.
Add the diced tomatoes, vegetable broth, dried oregano, and sugar to the pot. Stir well to combine all ingredients. Bring the mixture to a gentle boil, then lower the heat to simmer uncovered for about 20-25 minutes.
Once the soup is well simmered, remove it from the heat and allow it to cool slightly. Use an immersion blender directly in the pot to puree the soup until it reaches your desired consistency.
After blending, stir in the chopped fresh basil, then season generously with salt and freshly cracked black pepper. If desired, incorporate the heavy cream to deepen the flavor and richness. Heat the soup gently over low heat until warmed through, but avoid boiling.
Just before serving, taste and adjust the seasoning if needed, adding more salt or pepper as desired.
Notes
Ladle the hot soup into warm bowls, garnish with fresh basil leaves and a drizzle of olive oil. Serve with crusty bread.