Heat olive oil in a large pot over medium heat. Sauté onion, carrot, and celery for about 5 minutes until softened.,Add garlic, red pepper flakes, and tomato paste. Cook for 1–2 minutes until fragrant.,Deglaze the pot with a splash of balsamic vinegar. Add whole plum tomatoes, chicken broth, all seasonings, and the bay leaf. Stir, cover, and simmer on medium-low heat for 20 minutes, stirring occasionally.,Add fresh basil. Blend the soup with an immersion blender until smooth (or cool slightly and use a countertop blender).,Stir in heavy cream, sugar, salt, and pepper. Adjust seasoning to taste.,Serve hot with a swirl of balsamic glaze and a grilled cheese on the side if desired.