Heat 1 tablespoon olive oil in a large Dutch oven or heavy pot over medium-high heat. Add 1 finely chopped onion and cook for 4–5 minutes until softened.
Stir in 1 ounce grated unsweetened chocolate, 2 teaspoons minced garlic, 2 tablespoons chili powder, 1 tablespoon dried oregano, 1 teaspoon ground cinnamon, ¼ teaspoon ground allspice, and ¼ teaspoon ground cloves. Cook for about 30 seconds until fragrant.
Pour in 2 cups chicken broth, 2 cups water, 2 cans (8 ounces each) tomato sauce, 2 tablespoons tomato paste, 2 tablespoons apple cider vinegar, ½ teaspoon sugar, and 2 teaspoons Worcestershire sauce. Stir to combine.
Add 2 pounds ground beef to the pot, breaking it up with a spoon as you stir. Add 1 bay leaf and bring the mixture to a gentle boil.
Reduce the heat to low and simmer uncovered for 1 hour, stirring occasionally, until the beef is fully cooked and the chili has thickened.
Stir in ½ teaspoon salt and ½ teaspoon red pepper flakes.
Remove the bay leaf and serve over spaghetti with your desired toppings. Enjoy!
Notes
Refrigerate the leftovers in an airtight container for up to 5 days.