Heat the olive oil over medium heat in a large Dutch oven or heavy-duty pot. Add the Italian sausage and cook, undisturbed, for 3–5 minutes until the underside is well browned. Stir and continue cooking, breaking it up, until nicely browned and a fond forms on the bottom of the pot.1 tablespoon extra-virgin olive oil, ½ pound Italian sausage
Use a slotted spoon to transfer the sausage to a bowl or plate. Cover and set aside.
If there's more than 2 tablespoons of drippings from the Italian sausage remove any excess and discard. (I use Johnsonville Italian sausage which isn't very fatty.)
Reduce the heat slightly and add the onion, bell pepper, and celery to the pot. Cook for 3-4 minutes, stirring and scraping up the browned bits from the bottom of the pot. 1 large sweet onion, 1 large yellow bell pepper, 2 medium stalks celery
Add the garlic and cook for 30 seconds, stirring constantly. Stir in the tomato paste and Italian seasoning and cook for 3-4 minutes, until the tomato paste deepens in color (caramelizes). 6 medium cloves garlic, ¼ cup tomato paste, 4 teaspoons Italian seasoning
Add the crushed tomatoes, 6 cups of the chicken broth, carrots, beans, roasted red peppers (plus reserved liquid), rosemary, bay leaves, pesto, brown sugar, baking soda, salt, and pepper. (The mixture will foam briefly after adding the baking soda -this is normal.) 28 ounces crushed, fire-roasted tomatoes, 6-8 cups low-sodium chicken broth, 3 medium carrots, 15.5 ounces navy or cannellini beans, drained and rinsed, 15.5 ounces dark red kidney beans, drained and rinsed, 7 ounces roasted red peppers, diced (reserve liquid),1 tablespoon finely chopped fresh rosemary, 2 medium bay leaves, ¼ cup pesto, 2 teaspoons brown sugar, 1 teaspoon baking soda, 2 teaspoons kosher salt, ¾ teaspoon freshly ground black pepper
Bring to a boil, then reduce heat to maintain a steady simmer. Cook for 30 minutes, stirring occasionally.