Step 1: Prepare Your Oven and Cook the Beef

1. Preheat Oven: Position a rack in the center of your oven and preheat to 350°F (175°C). Lightly grease a 9×13 inch baking dish.

2. Brown the Beef: In a large skillet, cook the ground beef over medium-high heat, breaking it apart with a spoon, until it is fully browned and no pink remains.

3. Drain Thoroughly: Drain off all the excess grease from the skillet. This is a crucial step to prevent a greasy casserole.

4. Season the Beef: Return the skillet with the drained beef to the heat. Sprinkle the packet of taco seasoning over the meat and stir to combine. Cook for another minute to toast the spices and let the flavor bloom. Remove from heat.

Step 2: Create the Creamy Filling

1. Combine Ingredients: In a large mixing bowl, combine the cooked taco meat, the can of cream of chicken soup, the undrained can of Rotel, the drained corn, the rinsed black beans (if using), and 1 cup of the shredded cheese.

2. Stir to Combine: Stir everything together until it is well mixed. If the mixture seems overly thick, you can stir in up to a ½ cup of milk or water to reach a more spreadable consistency.

Step 3: The Art of Layering

1. First Layer (The Base): Coarsely crush about half of the bag of Doritos. Don’t turn them into dust; you want some larger pieces for texture. Create an even layer of the crushed chips on the bottom of your prepared 9×13 inch baking dish.

2. Second Layer (The Filling): Spoon the prepared ground beef mixture evenly over the top of the crushed Doritos layer. Use a spatula to spread it out to the edges of the dish.

3. Third Layer (The Topping): Sprinkle the remaining 1 cup of shredded cheese evenly over the beef filling.

4. Fourth Layer (The Crunch): Lightly crush the remaining Doritos from the bag and sprinkle them evenly over the top of the cheese.

Step 4: Bake to Bubbly, Golden Perfection

1. Bake: Place the casserole dish in the preheated oven and bake, uncovered, for 25 to 30 minutes. The casserole is done when the cheese is fully melted and the filling is hot and bubbly around the edges.

2. Rest: This is an important step! Let the casserole rest on a wire rack for 10-15 minutes before serving. This allows it to set up, making it much easier to slice and serve without falling apart.

Step 5: Garnish and Serve

1. Load it Up: Serve the casserole warm, topped with generous dollops of sour cream, chopped cilantro, sliced jalapeños, or any of your favorite taco toppings.