5ouncessourdough breadcrust removed and cut into 1-inch cubes
kosher saltto taste
Heat butter and olive oil in a large saucepan over medium heat until sizzling. Add onion, carrot, celery and garlic; cook and stir until onion is translucent, about 5 minutes. Add tomatoes, water, salt, pepper, crushed red pepper and basil. Stir and bring to boil; reduce heat and simmer 15 minutes.
To finish the soup, remove from heat and stir in cream; blend in the pan with an immersion blender or blend in batches in a traditional blender. (Important note: Blending hot liquids in a traditional blender will blow the lid off which will make a mess and could burn you. Instead, use a towel to cover the top of of the pitcher while blending instead of the lid. )
Return blended soup to pan and season to taste with salt and pepper; reheat to simmer if needed.
Meanwhile make the croutons: Preheat oven to 400˚F. Add bread cubes to a medium bowl and drizzle with olive oil; toss to coat. Spread cubes in a single layer on a baking sheet and season to taste with kosher salt. Bake 15 to 20 minutes until golden and crisp. Remove from oven and set aside.