Slow-Cooked Cannellini Beans and Sausages

Ingredients

• 3 Tbs. olive oil
• 2 lb. kielbasa sausages
• 1 large yellow onion, diced
• 3 celery stalks, diced
• 2 red bell peppers, seeded and diced
• 1 Tbs. tomato paste
• 3 garlic cloves, thinly sliced
• Red pepper flakes, to taste (optional)
• 2 cups chicken stock
• 2 cups water
• 1 bay leaf
• 1 fresh thyme sprig
• 1 fresh rosemary sprig
• 1 fresh sage sprig
• 1 1/2 lb. dried cannellini beans, rinsed, soaked overnight and drained
• 1 can (14 1/2 oz.) diced tomatoes, drained
• 1 cup fresh bread crumbs
• 1 Tbs. unsalted butter, melted
• Salt
• freshly ground black pepper
• 1/4 cup chopped fresh flat-leaf parsley
• 6 oz. baby spinach
• Crostini for serving