Heat 1 tablespoon of olive oil in a large Dutch oven or heavy-bottomed pot over medium-high heat. Add the sliced chicken sausage in a single layer and cook for 3 to 4 minutes, turning once or twice, until golden brown on the outside. Remove to a plate and set aside.

Add the remaining tablespoon of olive oil to the same pot. Add the onion, carrots, celery, salt, and pepper. Cook for 6 to 7 minutes, stirring occasionally, until the vegetables soften and the onion turns translucent.

Stir in the minced garlic, tomato paste, and Italian seasoning. Cook for about one minute, stirring constantly, until fragrant. The tomato paste will darken slightly and that is normal.

Pour in the beef broth and scrape up any browned bits from the bottom of the pot. Add the potatoes, drained white beans, and the browned sausage. Stir and bring to a boil over high heat.

Once boiling, reduce the heat to low and cover the pot with a lid. Let the stew simmer for 25 to 30 minutes, or until the potatoes are completely tender when pierced with a fork.

Stir in the fresh spinach and cook for 1 to 2 minutes until wilted. Taste and adjust salt and pepper as needed. Serve topped with Parmesan, fresh parsley, and a squeeze of lemon if desired.