Heat olive oil in a large pot over medium heat. Add onions and sauté until translucent, about 2–3 minutes.
Stir in minced garlic and cook for an additional 1 minute.
Add ground beef and cook until fully browned, breaking it up finely. Drain excess fat if needed.
Add chili powder, cinnamon, allspice, cloves, cocoa powder, cumin, paprika, salt, and pepper. Stir for 1 minute to toast the spices.
Stir in Worcestershire sauce, apple cider vinegar, beef broth, tomato sauce, and brown sugar.
Bring to a simmer, then reduce heat to low. Let it simmer uncovered for 1.5–2 hours, stirring occasionally, until thickened.
Optional: Stir in dark chocolate at the end and let it melt fully into the chili.
Serve over cooked spaghetti or hot dogs. Build it “5-way” style if desired:
1-Way: Just chili
2-Way: Chili + Spaghetti
3-Way: + Shredded cheese
4-Way: + Diced onions
5-Way: + Kidney beans