Preheat your oven to 350 degrees Fahrenheit. Make sure your oven is fully preheated before you put in the casserole—this is crucial for an evenly baked dish.
While the oven is heating, grab a 13 x 9 inch baking dish and spray it with nonstick cooking spray. This will ensure your flavors don’t stick and helps with easy cleanup.
In a large skillet over medium high heat, add the finely chopped onions and ground beef. As you cook, stir occasionally until the onions are soft and the beef is no longer pink. Make sure to break the meat apart for better cooking. We want to drain off any extra grease afterward.
Next, stir in the taco seasoning and water, bringing the mixture to a boil. The spices will start to release their beautiful aromas as they mix with the beef.
Once boiling, reduce the heat to medium low. Stir in the pinto beans, Rotel, and sour cream. Allow this to cook for about 8 to 10 minutes or until heated and slightly thickened. Keep an eye on the texture; it should be creamy but not runny.
Now, it’s time to assemble! Start with a single layer of corn chips—about half of the bag—at the bottom of the prepared baking dish. This will add a delightful crunch.
Sprinkle 1 cup of the shredded cheese on top of the corn chips. Feel free to add more if you’re feeling cheesy!
Layer the seasoned beef mixture over the cheese. Spread it out evenly so every bite has a taste of that flavorful filling.
Top the casserole with the remaining shredded cheese, creating a gooey blanket over the entire dish.
Cover the baking dish with foil and bake in the preheated oven for about 15 minutes. This helps to melt the cheese and warm the flavors.
After 15 minutes, remove the foil and continue baking for an additional 5 minutes. This allows the cheese to become bubbly and golden. You'll know it’s ready when the edges look deliciously bubbly!
Once done, take the casserole out of the oven and let it cool for a few minutes. Top with the remaining corn chips and your favorite toppings like green onions, guacamole, salsa, and jalapenos. Serve immediately and enjoy your delicious Walking Taco Casserole!
