Instructions:

1. Preheat your oven to 375°F (190°C). Lightly grease an 8x8 inch (or similar sized) baking dish.
2. Cook the bacon: In a large skillet over medium heat, cook the bacon until crispy. Remove bacon, drain on paper towels, and crumble once cooled. You may reserve 1 tablespoon of the bacon fat for extra flavor, if desired.
3. Prepare potatoes: Place the diced potatoes in a large pot and cover with cold water. Bring to a boil, then reduce heat and simmer for 5-7 minutes, or until the potatoes are just tender when pierced with a fork but still hold their shape (al dente). Drain thoroughly.
4. Combine: In a large bowl, gently toss the drained, par-cooked potatoes with the melted butter, salt, and black pepper.
5. Layer the bake: Spread half of the seasoned potatoes evenly in the prepared baking dish. Sprinkle with half of the crumbled bacon and half of the shredded cheese.
6. Repeat layer: Place the remaining potatoes over the first layer, then sprinkle with the rest of the crumbled bacon and the remaining shredded cheese.
7. Add liquid: Pour the milk evenly over the top of the casserole. If you reserved bacon fat, drizzle it over the milk.
8. Bake: Bake for 25-30 minutes, or until the potatoes are heated through, the cheese is melted and bubbly, and the top is lightly golden brown.
9. Serve: Let the bake stand for 5 minutes before serving to allow it to set slightly.