In a large pot, sauté onion, garlic, bay leaf and pepper flakes in olive oil over medium-high heat until translucent.
Add whole tomatoes and their juice mashing slightly with a potato masher.
Add cubed bread and brown sugar. Bring to a boil, reduce heat and simmer for 5 minutes, stirring occasionally, remove bay leaf.
You can use an immersion blender to process the soup directly in the pot or blend in batches, using a ladle, fill a blender or food processor 2/3 full, adding 1 T. olive oil to each batch blended, blend until smooth. Add each batch back to a clean pot.
Return to heat and add chicken broth, bring to a boil. Remove from heat, season to taste with salt & pepper if needed.
Pour into individual bowls and top with croutons, chives and a drizzle of olive oil.
Cook's Note: To complete the meal, serve with grilled cheese sandwiches.