01 - Heat vegetable oil in a large skillet over medium heat. Add chopped onion and cook for 2–3 minutes until softened and translucent.
02 - Stir in minced garlic and cook for 30 seconds until fragrant, being careful not to burn it.
03 - Add ground beef to the skillet. Cook, breaking up meat with a wooden spoon, until browned and cooked through, about 5–7 minutes. Drain excess fat if needed.
04 - Stir in tomato paste, chili powder, cumin, smoked paprika, oregano, cayenne, salt, and pepper. Mix thoroughly to distribute spices evenly.
05 - Pour in beef broth or water. Simmer uncovered for 4–5 minutes until mixture thickens slightly, stirring occasionally. Adjust seasoning to taste.
06 - While beef simmers, warm hard taco shells according to package instructions until crispy and heated through.
07 - Fill each warm shell with seasoned beef mixture. Top with shredded lettuce, diced tomatoes, cheese, sour cream, green onions, cilantro, and sliced jalapeño if desired.
08 - Arrange tacos on a serving platter and serve immediately with lime wedges on the side for squeezing.