1. Preheat your oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish.
2. In a skillet over medium heat, cook the ground beef, onion, and garlic until the meat is browned and the onion is soft. Drain excess fat.
3. Stir in the taco seasoning, tomato sauce, and water. Simmer for 5-7 minutes until the mixture thickens slightly.
4. Spread a thin layer of the beef mixture on the bottom of the baking dish. Place two tortillas over it, slightly overlapping.
5. Add another layer of beef mixture, followed by a layer of shredded cheese. Repeat the layering process (tortillas, beef, cheese) until all ingredients are used, ending with a generous layer of cheese on top.
6. Cover the dish with foil and bake for 20 minutes. Remove the foil and bake for an additional 10 minutes or until the cheese is golden and bubbly.
7. Let the dish cool for 5 minutes before garnishing with sour cream, sliced jalapeños, and cilantro. Serve warm.