I learned this recipe in a restaurant, my family asks me to do it always!

Season the beef: Rub beef with salt and pepper.
Prepare potato mixture: Grate potatoes. Combine mozzarella, cottage cheese, mayonnaise, and mustard.
Cook potatoes and onions: Sauté grated potatoes and sliced onion in olive oil until golden brown.
Combine ingredients: Add seasoned beef to the pan with potatoes and onions. Pour cheese mixture over the top.
Simmer: Cover and simmer for 15-20 minutes, or until beef is cooked through.
Serve: Enjoy!