Heat the olive oil in a large pot or Dutch oven over medium heat. Add the diced onion and minced garlic, and sauté until softened, about 5 minutes.

Add the ground beef to the pot, breaking it apart with a spoon, and cook until browned and no longer pink, about 8-10 minutes.

Stir in the diced bell pepper, kidney beans, black beans, diced tomatoes (with their juices), beef broth, chili powder, ground cumin, paprika, dried oregano, salt, and pepper.

Bring the chili to a simmer, then reduce the heat to low and let it simmer, uncovered, for about 30-40 minutes, stirring occasionally, until the flavors have melded together and the chili has thickened to your desired consistency.

Taste the chili and adjust the seasoning as needed with additional salt and pepper.

Serve the chili hot, garnished with your favorite toppings such as shredded cheese, chopped green onions, sour cream, avocado slices, or cilantro.

Enjoy this classic beef chili with your favorite sides, such as cornbread, rice, or tortilla chips.