Preheat oven to 375°.
Heat a Dutch oven over medium-high heat. Coat pan with cooking spray. Add onion and turkey sausage to pan; sauté for 5 minutes or until browned. Add garlic, and sauté 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.
Place bread in a food processor, and pulse 10 times or until coarse crumbs measure 1 1/2 cups.
Sprinkle breadcrumbs evenly over bean mixture, and lightly coat with cooking spray. Bake at 375° for 15 minutes or until browned. Discard bay leaf. Sprinkle with parsley.