First, preheat your oven to 350 or 180 degrees C.
Place your ground beef and onion in a skillet over medium to high heat. Cook for about 5 minutes until the meat is browned in color, and the onions are softened.
Mix the rosemary, garlic powder, soup, heavy cream, broth, salt, and pepper in a large bowl.
Layer ½ of the sliced potatoes in the bottom of a well-greased 9x13 inch baking dish.
Add ⅓ of the soup mixture and ½ of the meat mixture.
Place another layer of the potatoes, then ⅓ of the soup mixture, and the rest of the meat mixture.
Top with the rest of the soup mixture and sprinkle with grated cheese.
Cover with a piece of aluminum foil and bake for about 90 minutes.
Serve and enjoy.