Step 1: Heat olive oil in a large skillet over medium-high heat. Add ground turkey and cook, breaking it up with a spoon, until browned. Drain any excess fat and transfer the turkey to your slow cooker.
Step 2: In the same skillet, add the diced onion and bell pepper. Sauté for 5-7 minutes until softened. Add the minced garlic and cook for another minute until fragrant.
Step 3: Stir in the chili powder, ground cumin, smoked paprika, dried oregano, and cayenne pepper (if using). Cook for 1 minute, stirring constantly, to toast the spices and release their aromas. Transfer the onion mixture to the slow cooker with the turkey.
Step 4: Add the crushed tomatoes, diced tomatoes (undrained), rinsed black beans, rinsed kidney beans, chicken broth, and bay leaf to the slow cooker. Stir everything together until well combined.
Step 5: Season with salt and freshly ground black pepper to taste. Be generous but remember you can always add more later.
Step 6: Cover the slow cooker and cook on LOW for 6-8 hours or on HIGH for 3-4 hours, or until the chili is heated through and flavors have melded. The longer it simmers, the more developed the flavors will be.
Step 7: Remove the bay leaf before serving. Ladle the chili into bowls and serve hot with your favorite toppings such as shredded cheese, a dollop of sour cream or Greek yogurt, diced avocado, and fresh cilantro.