Before you start cooking, prepare all your ingredients: finely chop the onion, mince the garlic, and roughly chop the fresh basil (reserving a few leaves for garnish if desired).

In a large pot or Dutch oven, heat the olive oil over medium heat until shimmering.

Add the chopped onion to the pot and cook, stirring occasionally, for 5-7 minutes until it's softened and translucent. Add the minced garlic and cook for another minute until fragrant, being careful not to let it brown or burn.

Pour in the two cans of diced tomatoes (undrained) and the vegetable broth. Stir in the granulated sugar, salt, and black pepper.

Bring the soup mixture to a gentle boil, then reduce the heat to low. Cover the pot and let the soup simmer for 20-25 minutes, allowing the flavours to deepen and meld beautifully.

Remove the pot from the heat. Stir in the roughly chopped fresh basil. The residual heat will wilt the basil and infuse its aroma into the soup.

Using an immersion blender, carefully blend the soup directly in the pot until it reaches your desired smoothness. If you don't have an immersion blender, carefully transfer the soup in batches to a regular blender (fill only halfway, vent the lid, and cover with a kitchen towel to prevent hot splashes). Blend until smooth, then return the blended soup to the pot.

Taste the soup and adjust the seasoning as needed. You might want to add a little more salt, pepper, or sugar to balance the flavors. If the soup is too thick for your preference, add a splash more vegetable broth or water until it reaches the desired consistency.

Ladle the hot soup into bowls. For an extra touch of richness, drizzle with a little heavy cream or crème fraîche, and garnish with a fresh basil leaf. Serve immediately with crusty bread for dipping.