01 - Heat olive oil in a large skillet over medium heat. Add chopped onion and sauté for 2–3 minutes until softened.
02 - Add minced garlic and cook for 30 seconds until fragrant.
03 - Add ground beef to the skillet. Cook, breaking it up with a spatula, until browned and cooked through, approximately 5–7 minutes. Drain excess fat if necessary.
04 - Stir in tomato paste, chili powder, cumin, smoked paprika, oregano, salt, black pepper, and cayenne. Cook for 1 minute to release aromatics.
05 - Pour in beef or chicken broth. Simmer for 3–4 minutes until liquid reduces to a rich, saucy consistency. Adjust seasoning to taste.
06 - Meanwhile, warm hard taco shells according to package instructions, typically 3–5 minutes in a 350°F oven.
07 - Fill each taco shell with a generous spoonful of seasoned beef mixture.
08 - Top each taco with shredded lettuce, cheese, diced tomato, sour cream, olives, cilantro, avocado, and salsa as desired. Serve immediately.