Cut the chicken breast into small cubes.
Preheat the frying pan. When hot, add 1 tablespoon of olive oil and chicken cubes. Cook at medium heat, stirring occasionally, until the chicken is cooked, about 7-10 minutes (depending on done-ness preference).
In a large pot over medium-high heat, add butter and olive oil. Chop and add onion, garlic, carrots, and celery. Saute until tender and fragrant, about 4 minutes.
Stir in zucchini and bell pepper and cook until slightly softened, about another 2 minutes.
Sprinkle in almond flour to create a roux and cook for another minute.
Slowly add the chicken broth while continuously stirring until it starts to thicken and comes together.
Stir in Italian seasoning, red pepper flakes (optional), cannellini beans, and canned tomatoes. Bring to a boil, stirring frequently.
Add the cooked chicken cubes. Reduce heat to low and simmer uncovered for 20 minutes.
Stir in spinach leaves and apple cider vinegar. Cook another 3 minutes or until everything is heated through. Season with salt and pepper to taste.
Serve hot. Top with fresh parsley (optional).