01 - Preheat oven to 350°F. Arrange hard taco shells on a baking sheet and warm in the oven for 5 minutes until crisped.
02 - Heat a large skillet over medium heat. Add ground beef and cook, breaking apart with a wooden spoon, until browned throughout, about 5–6 minutes. Drain excess fat if needed.
03 - Add chopped onion and minced garlic to the browned beef. Cook for 2–3 minutes until onion is softened and fragrant.
04 - Stir in chili powder, cumin, smoked paprika, dried oregano, salt, and black pepper. Cook for 1 minute to toast the spices and release their oils.
05 - Pour in tomato sauce and water, stirring to combine all ingredients. Simmer for 3–4 minutes until the mixture slightly thickens. Remove from heat.
06 - Spoon a generous portion of seasoned beef into each warmed taco shell. Top immediately with shredded cheddar cheese while the filling is hot so it melts.
07 - Layer shredded lettuce, diced tomatoes, and any optional toppings including sour cream, black olives, green onions, and fresh cilantro as desired.
08 - Arrange tacos on a serving platter and serve immediately with salsa on the side for added flavor and freshness.