Preheat oven to 375 degrees. Grease a 9 x 13 baking dish and set aside.
Scrub potatoes clean. Cut potatoes using a sharp knife or a mandolin into 1/4" thick slices. Place in a large bowl of water.
In a large skillet, heat 2 TBS cooking oil over medium high heat. Add onion and cook until softened. Break in ground beef and cook until beef is no longer pink. Drain excess grease out.
Stir in garlic, salt, pepper, Italian seasoning, and paprika. Turn off heat.
Layer 1/3 potato slices in prepared baking dish overlapping in one layer. Spread 1/3 of the ground beef mixture evenly over the potatoes. Sprinkle 1/3 of the shredded cheese over the ground beef.
Repeat with layers 2 & 3 the same using the remaining potatoes, ground beef, and cheese.
Mix together in a small bowl the beef broth and milk. Pour evenly over the casserole.
Cover casserole dish tightly with foil. Bake in preheated oven for 1 hour. Remove foil and sprinkle the casserole with parmesan cheese. Place back in oven uncovered and bake for 15 or so minutes until potatoes are tender and cheese has melted and is golden brown.
Sprinkle with dried parsley. Let sit for 5 minutes before serving.