Heat a Dutch oven over medium-high heat. Coat pan with cooking spray. Add onion and turkey sausage to pan; saute for 5 minutes or until browned. Add garlic, and saute for 2 minutes. Stir in chicken broth, scraping pan to loosen browned bits. Stir in 2 tablespoons brown sugar, tomato paste, dried thyme, freshly ground black pepper, cannellini beans, and bay leaf. Add ground red pepper, if desired. Bring to a boil; cover, reduce heat, and simmer for 5 minutes. Remove from heat.