01 - Preheat oven to 350°F. Place hard taco shells on a baking sheet and warm for 5–7 minutes, or according to package instructions.
02 - Heat a large skillet over medium heat. Add ground beef and cook, breaking it up with a spatula, until browned, about 5–6 minutes. Drain excess fat if needed.
03 - Add diced onion to the skillet and cook for 2 minutes until softened. Stir in minced garlic and cook for 30 seconds.
04 - Mix in tomato paste, chili powder, cumin, smoked paprika, oregano, salt, and pepper. Cook for 1 minute, stirring to coat the beef evenly.
05 - Pour in beef broth or water. Reduce heat to low and simmer for 5–7 minutes, stirring occasionally, until most of the liquid has evaporated and the mixture is thick and saucy. Taste and adjust seasoning.
06 - Fill each warm taco shell with a generous spoonful of beef mixture. Top with lettuce, tomatoes, cheddar cheese, and any other desired toppings.
07 - Serve immediately with lime wedges on the side.