Preheat your oven to 400°F (200°C).

In a large skillet, add your ground beef and chopped onion over medium heat. Cook for about 7–10 minutes until browned and translucent.

Season the mixture with salt, black pepper, garlic powder, and Worcestershire sauce if using. Stir well.

Grease a 9-inch pie dish with cooking spray or butter. Spread the cooked meat and onion mixture evenly across the bottom.

Sprinkle the shredded cheddar cheese evenly over the beef layer.

In a separate bowl, whisk together the eggs, milk, flour, and a pinch of salt until smooth.

Carefully pour the custard batter over the meat and cheese layers in the pie dish.

Place the assembled pie in the preheated oven and bake for 25–30 minutes.

Once baked, let the pie cool slightly for about 5–10 minutes before serving.