01 - Heat 1 tablespoon vegetable oil in a large skillet over medium heat. Add the finely chopped onion and cook for 3 minutes until softened. Add the minced garlic and cook for 1 additional minute until fragrant.
02 - Add the ground beef to the skillet. Cook, breaking it apart with a spoon, until evenly browned and cooked through, approximately 7 minutes. Drain any excess grease if needed.
03 - Stir in the chili powder, ground cumin, smoked paprika, dried oregano, cayenne pepper, salt, and black pepper. Toast the spices for 1 minute until fragrant and well incorporated into the meat.
04 - Add the tomato paste and stir thoroughly to coat the beef. Pour in the beef broth and bring to a simmer. Cook for 3 to 4 minutes, stirring occasionally, until most of the liquid has been absorbed and the filling is saucy but not watery. Remove from heat and set aside.
05 - Pour vegetable oil to a depth of about 1 inch into a deep skillet or heavy-bottomed pot and heat over medium-high heat. Using tongs, carefully lay each tortilla in the hot oil, then immediately fold it in half to form a taco shell shape. Fry for 1 to 2 minutes per side until crisp and golden brown. Transfer to paper towels to drain.
06 - Spoon the seasoned beef filling into each crispy shell while still warm. Sprinkle generously with shredded cheddar or Monterey Jack cheese so it melts from the residual heat.
07 - Top each taco with your choice of shredded lettuce, diced tomato, sliced jalapeños, diced red onion, sour cream, fresh cilantro, and salsa. Serve immediately with lime wedges on the side.