Sauté the Base Vegetables: Heat the olive oil in a large stockpot or Dutch oven over a medium-low heat. Add the chopped onion, carrots, and celery. Cook gently for 10-12 minutes, stirring occasionally, until the vegetables are very soft but not browned.

Add Aromatics: Add the minced garlic and cook for another minute until fragrant. Stir in the tomato purée and cook for a further minute, allowing it to toast slightly, which deepens its flavour.

Incorporate Tomatoes and Stock: Pour in the two tins of whole plum tomatoes, breaking them up with the back of a wooden spoon. Add the vegetable stock, sugar (if using), and the bay leaf. Season generously with salt and pepper.

Simmer the Soup: Bring the soup to a gentle simmer, then reduce the heat to low, cover the pot with a lid, and let it cook for at least 20 minutes. This gives the flavours time to meld together beautifully. I find that a longer, slower simmer always yields a better result.

Blend Until Smooth: Remove the pot from the heat and take out the bay leaf. Use an immersion blender to blitz the soup directly in the pot until it is completely smooth and velvety. Alternatively, carefully transfer the soup in batches to a stand blender and blend until smooth (be sure to allow steam to escape).

Finish with Cream and Basil: Return the pot to a very low heat. Stir in the double cream and the torn basil leaves. Gently heat through for a minute or two, but do not allow the soup to boil, as this can cause the cream to split. Taste and adjust the seasoning with more salt and pepper if needed.

Serve: Ladle the hot soup into bowls. Garnish with an extra drizzle of olive oil, a swirl of cream, or some fresh basil leaves before serving.