Place a dutch oven over medium high heat; add olive oil and heat until it shimmers. Add the sausage to the pot and break into crumbled with a wooden spoon. Continue cooking, stirring occasionally, until no longer pink, about 8 minutes.
Add onion, carrots and celery to the pot. Saute, stirring occasionally, until the onions are translucent and the vegetables are soft, 5-6 minutes. Add garlic and italian seasoning and cook 1 minute more, stirring continuously.
Add the can of white beans (including the canning liquid) along with the diced tomatoes and three cups of broth. Season with cracked black pepper and red pepper flakes (if using), but hold the salt until the end. Stir to combine and top with thyme bundle.
Bring the liquid to a boil, then reduce heat to medium low and simmer uncovered 10-15 minutes until the flavors meld. Taste for seasoning and adjust with salt or pepper if needed.
Ladle into soup bowls, garnish with chopped parsley, and serve immediately. Leftovers will keep in a sealed container in the fridge for up about a week. Freeze in an airtight container for up to 3 months.
