Heat the olive oil in a large pot over medium heat. Add the onion and cook for ~4 minutes or until softened. Add the garlic and dried basil and cook for ~1 more minute or until fragrant.
Add the tomatoes and their juices, tomato paste, diced tomatoes, broth, coconut milk, salt, pepper, and maple syrup. Cover and bring to a simmer and let cook for 15-20 minutes. The longer it simmers, the deeper the flavor.
Turn off the heat and use an immersion blender to purée the soup (or if using a regular blender, let the soup cool first to avoid an explosion).
Bring soup back to a simmer over medium heat until warmed. Taste and adjust seasonings as needed, adding more maple syrup to balance the acidity, coconut milk for creaminess, or salt for overall flavor. If you prefer a thicker soup, remove the lid and simmer uncovered, stirring occasionally, until desired consistency is reached.
Leftovers will keep covered in the refrigerator for 4-5 days or in the freezer for 1-2 months.
*To make croutons, slice day-old bread (we like sourdough) into cubes (it can be easier to do this with scissors if your bread is difficult to cut). Add to a baking sheet or oven-safe cast-iron pan and toss with a little oil, salt, pepper, and garlic powder. Bake for 5-10 minutes at 400 degrees F (204 C), or until golden brown and toasty. *Recipe as written makes ~8 cups (2 liters) soup. *Nutrition information is a rough estimate calculated without optional ingredients. *Adapted from the Creamy Tomato & Herb Bisque in our Everyday Cooking cookbook.