In a large skillet over medium-high heat, brown the ground beef alongside the diced onion for 5–7 minutes, or until the meat is no longer pink and the onions become translucent. Stir in minced garlic, cooking for an additional minute until fragrant.

Carefully transfer the browned beef and onion mixture to your slow cooker, scraping in any tasty bits left in the skillet.

Add rinsed kidney beans, black beans, diced tomatoes (with juice), tomato sauce, and beef broth into the slow cooker. Stir everything well to combine.

Sprinkle chili powder, ground cumin, smoked paprika, dried oregano, unsweetened cocoa powder, salt, and black pepper over the mixture in the slow cooker and mix thoroughly.

Cover the slow cooker and cook on LOW for 6–8 hours or HIGH for 3–4 hours.

Once cooked, ladle the warm chili into bowls and serve with your favorite toppings like shredded cheese, diced onions, or sour cream.