Preheat your oven to 400°F (200°C).

Line a baking sheet with foil or parchment paper and spray with nonstick cooking spray.

In a large bowl, combine the frozen hash browns, shredded cheese, diced onions, olive oil, salt, and pepper. Toss until evenly coated.

Stir in melted butter, ensuring it coats all the ingredients thoroughly.

Spread the mixture evenly across the prepared baking sheet in a single layer.

Bake for approximately 28 minutes, checking after 20 minutes for golden brown color and crispy edges.

Remove from the oven, let cool for a couple of minutes, and cut into squares for serving.