Heat oil in a pot over medium heat
Add chopped onion and cook until softened
Add minced garlic and cook briefly
Add ground beef or leave it out for vegetarian chili beans
Cook until the meat is browned, if using
Stir in chili powder, cumin, paprika, salt, and black pepper
Add tomato sauce or diced tomatoes
Add cooked beans or canned beans, drained and rinsed
Add a little water or broth if needed
Stir well and bring to a simmer
Reduce heat and cook until thickened
Taste and adjust seasoning
Serve hot