Step 1: Sauté the Vegetables
In a large Dutch oven or heavy-bottomed pot, heat olive oil over medium heat.
Add diced onion, green bell pepper, red bell pepper, and minced garlic. Sauté for 5 minutes, or until the vegetables are softened.
Step 2: Brown the Ground Beef
Add ground beef to the pot with the vegetables. Cook until browned, breaking it up with a wooden spoon as it cooks (about 6-8 minutes). Drain any excess fat.
Step 3: Add the Remaining Ingredients
Stir in the kidney beans, black beans, diced tomatoes, crushed tomatoes, beef broth, and tomato paste.
Add chili powder, ground cumin, smoked paprika, oregano, salt, black pepper, and cayenne pepper, if using.
Stir well to combine all ingredients.
Step 4: Simmer the Chili
Bring the chili to a boil, then reduce the heat to low. Cover and simmer for at least 1 hour, stirring occasionally.
For deeper flavor, let the chili simmer for up to 2 hours on low.
Step 5: Taste and Adjust Seasonings
After simmering, taste the chili and adjust seasonings as needed.
Step 6: Serve
Ladle the chili into bowls and add desired toppings like shredded cheese, green onions, sour cream, and cilantro.