Preheat your oven to 400°F (200°C). Generously grease a 9×13-inch casserole dish with butter or non-stick cooking spray to prevent sticking.

Spread the sliced or cubed potatoes in an even layer in the prepared casserole dish. Sprinkle the chopped onion and bacon evenly over the potatoes. Distribute the diced butter all throughout the dish, making sure there’s plenty to melt into every nook and cranny. Season generously with salt and black pepper.

Cover the casserole dish tightly with aluminum foil. This step traps the steam, ensuring the potatoes cook through evenly while staying tender inside. Bake in the preheated oven for about 45 minutes.

After 45 minutes, remove the foil and give everything a gentle stir to redistribute the flavors. Turn on your oven’s broiler setting and broil for about 5 minutes, or until the top is crispy and golden brown. Stir every minute or so while broiling to promote even browning and prevent burning.

Once everything is browned and crisp, remove the dish from the oven and serve immediately while piping hot. These potatoes are delicious on their own, or alongside eggs, sausage, steak, or even a fresh garden salad.