Heat a large skillet over medium heat. Add the ground beef and diced onion. Cook until the beef is browned and the onions are soft. Drain excess fat.

Stir in salt, pepper, and Worcestershire sauce. Cook for an additional 2 minutes.

Lightly grease a 9-inch pie plate. Spread the beef and onion mixture evenly across the bottom.

Sprinkle shredded cheddar cheese over the hot beef.

In a small mixing bowl, whisk together milk, eggs, and flour or Bisquick until smooth. Pour the batter over the cheese and beef.

Place the dish in a preheated oven at 400 degrees Fahrenheit. Bake for about 25 to 30 minutes, until the surface is set and golden brown.

Allow the pie to rest for 5 to 10 minutes before slicing.