Preheat the oven to 375° F. Heat the oil in an 11 - 12-inch skillet over medium-high heat until shimmering.
Add the chopped onion cook until softened, 5 to 7 minutes. Add the beef and seasoning cook until lightly brown, breaking up the meat with a wooden spoon, for 5 to 8 minutes.
Stir in half of the rotel and tomato juice from the can. Bring to a simmer and cook until the mixture is thickened and nearly dry, about 10 minutes. Season with salt and pepper to taste.
Smooth down the ground beef with a spatula until level. Sprinkle with ½ cup cheese. Scatter the Fritos corn chips over the top, then sprinkle with the remaining ½ cup cheese.
Bake until the filling is bubbling and the top is spotty brown, about 15 minutes. Let the casserole cool for 10 minutes, then sprinkle with the green onions if using, remaining rotel (drained) with your choice of optional toppings.
Serve warm, with a side of salsa for a nice kick of flavor!
Notes
Pre-shredded cheese is the most convenient, but if you have the time-buy a block of cheese and shred it yourself. Freshly shredded cheese melts better than packaged shreds, and it tastes better, too!Recipe Variations:
Add beans: Mix in black beans, kidney beans, or pinto beans for extra protein and fiber.
Make it spicy: Stir in chopped jalapeños or a dash of hot sauce.
Top it off: Add guacamole, salsa, diced tomatoes, or more shredded cheese.
Go vegetarian: Omit the meat and use extra beans and veggies instead.
Storing Instructions:Store leftovers in an airtight container and use within 5 days.Make Ahead Instructions:
Fritos (and similar corn tortilla chips) quickly soak up any liquids that are nearby, and then they become mushy. So, to make the walking taco bake ahead for a freezer meal to bake later, it's important to assemble the casserole without chips. Make the recipe up to step 4, as written in the recipe card, below. Then, a couple of days before you want to cook the meal, transfer the dish to the fridge so it can thaw out. When it is thawed, add the chips and cheese.
Then, cover the dish and bake the Frito casserole at 350°F. oven for 45 minutes, removing the foil for the final 15 minutes of cooking time.