Brown the beef: Heat the oil in a large pot or Dutch oven over medium-high heat. Add the ground beef and cook, breaking it up, until browned with crispy edges, about 7–9 minutes.
Spoon off excess fat if needed, leaving about 2 tablespoons in the pot.
Sauté the vegetables: Add the onion, bell pepper, jalapeño, and mushrooms. Cook, stirring often, until the vegetables soften and most moisture cooks off, 6–8 minutes.
Add garlic and spices: Stir in the garlic, chili powder, cumin, smoked paprika, oregano, coriander, and cinnamon or cocoa. Cook 1 minute until fragrant.
Tomato base: Stir in the tomato paste and cook 1 minute to caramelize.
Add the diced tomatoes, tomato sauce, and beef broth. Season with salt and black pepper.
Simmer low and slow: Bring to a gentle simmer. Reduce heat to low, partially cover, and cook 30–45 minutes, stirring occasionally, until thick and glossy.
Add a splash of water or broth if it gets too thick.
Finish and balance: Stir in the apple cider vinegar or lime juice. Taste and adjust salt, pepper, and heat. For more depth, add a pinch more smoked paprika or a small square (about 1/2 ounce) of very dark chocolate (90%+), if desired.
Serve: Ladle into bowls and finish with your favorite keto-friendly toppings.
Serve with a side salad or over cauliflower rice.