Preheat your oven to 350°F (175°C).
Prepare a 9x13 inch baking dish by greasing it with butter or cooking spray.
Layer half of the sliced potatoes in the prepared baking dish, ensuring an even distribution.
Sprinkle half of the shredded cheese over the first layer of potatoes.
In a mixing bowl, combine heavy cream, milk, garlic powder, onion powder, salt, and pepper. Mix well.
Pour half of the cream mixture over the first layer of potatoes and cheese, making sure to cover them well.
Repeat the layering process with the remaining potatoes, cheese, and cream mixture.
Cover the baking dish with aluminum foil and bake for 45 minutes.
After 45 minutes, remove the foil and bake for an additional 15-20 minutes until the top is golden and bubbly.
Remove from the oven and let it cool slightly before serving. Garnish with chopped parsley if desired.