Begin by peeling and chopping your starchy potatoes into uniform cubes. Place them in a large pot filled with salted water and bring to a boil. Cook for about 15 minutes or until fork-tender; drain thoroughly.

Return the hot, drained potatoes to the pot and add butter, milk, garlic powder, salt, and pepper. Mash until smooth and creamy.

In a large skillet over medium heat, heat olive oil until shimmering. Add diced onion and minced garlic, sauté for 2-3 minutes until fragrant. Add ground beef and cook until browned, about 5-7 minutes.

Stir in tomato paste, Worcestershire sauce, mixed vegetables, and broth. Simmer for 5-7 minutes until thickened.

Spoon the savory beef filling into a 9x9-inch baking dish, spreading it evenly.

Transfer the cooled mashed potatoes into a piping bag fitted with a wide star tip. Pipe ghost shapes across the top of the beef filling.

Preheat the oven to 375°F (190°C) and bake for 20-25 minutes until the tops of the ghost potatoes turn lightly golden.