Heat the olive oil in a large stockpot or Dutch oven over medium-high heat.
Add the turkey sausage and cook for 5-7 minutes, breaking it into small crumbles with a wooden spoon until browned.
Incorporate the diced onion, carrots, and celery, sautéing for 6 minutes until the vegetables are translucent.
Add the garlic, oregano, and red pepper flakes, stirring for 60 seconds until fragrant.
Pour in the cannellini beans and the chicken bone broth.
Bring the mixture to a boil, then reduce heat to low and simmer for 20 minutes.
Optional: Use an immersion blender or the back of a spoon to mash a small portion of the beans directly in the pot to thicken the consistency.
Stir in the chopped kale and cook for 3 minutes until the greens are wilted but vibrant.
Add the lemon juice, salt, and pepper, stirring to combine.
Portion into bowls and serve immediately.