Prepare your ingredients: Dice the onion, bell pepper, and garlic. Measure out your spices and have your tomatoes and tomato paste ready.
Sauté the aromatics: Heat olive oil (or butter) in a large pot or Dutch oven over medium heat. Add the diced onion, bell pepper, and garlic, cooking for 3-4 minutes until softened.
Brown the ground beef: Add the ground beef to the pot, breaking it apart with a spoon. Cook until browned and cooked through (about 7 minutes).
Add spices and seasonings: Stir in the chili powder, cumin, smoked paprika, cayenne pepper, salt, and pepper. Let the spices toast for about 1 minute.
Add tomatoes: Pour in the diced tomatoes and tomato paste. Stir to combine, then reduce heat to low. Let the chili simmer for 30 minutes, stirring occasionally.
Thicken the chili (optional): If you prefer a thicker chili, sprinkle in the xanthan gum and stir until well combined. Let the chili simmer for an additional 5-10 minutes.
Serve: Once the chili has thickened to your liking, serve hot. Top with shredded cheese, sour cream, avocado slices, and fresh cilantro if desired. Enjoy!