Preheat your oven to 350°F. While it heats, warm 2 tablespoons of olive oil in a large oven-safe skillet over medium-high heat. Add the diced onion and minced garlic, sautéing for 5-7 minutes until softened and fragrant. Add the ground beef along with salt, pepper, and chili powder, breaking it up as it cooks for 7-8 minutes until browned throughout. Once cooked, transfer the beef mixture to a plate and set aside. I find cooking the aromatics first really develops their sweetness before the meat goes in, which adds depth to the whole dish.

In the same skillet, add the remaining 3 tablespoons of olive oil over medium-high heat. Spread the frozen hash browns evenly in the pan and cook undisturbed for 5-6 minutes until the bottom is golden and crispy. Flip the hash brown cake in sections and cook for another 3-4 minutes on the other side until evenly browned. This creates a sturdy, flavorful foundation that won't get soggy when the casserole bakes.

Spread the cooked beef mixture from Step 1 evenly over the hash browns, then top with the cheese. Transfer the skillet to the preheated 350°F oven and bake for 15 minutes until the cheese is melted and bubbly. I like to use a sharp cheddar or a blend for better flavor—it really makes the casserole taste richer.

Remove the casserole from the oven and let it rest for 2-3 minutes. Top each serving with crispy crumbled bacon, shredded lettuce, diced tomato, avocado slices, and jalapeño slices. Serve immediately while the casserole is still warm and the toppings stay fresh and crisp.