Preheat the oven to 350°F (175°C) and line a muffin tin with cupcake liners.
In a large bowl, combine ground beef, breadcrumbs, milk, ketchup, onion, egg, garlic powder, salt, black pepper, oregano, and thyme. Mix until well combined.
Divide the meat mixture evenly among the muffin cups, filling each about 2/3 full.
Bake in the preheated oven for 20-25 minutes, or until the meatloaf is cooked through and reaches an internal temperature of 160°F (70°C).
While the meatloaf cupcakes are baking, place the cubed potatoes in a large pot and cover with water. Bring to a boil and cook until tender, about 15-20 minutes.
Drain the potatoes and return them to the pot. Add butter, milk, garlic powder, salt, and pepper. Mash until smooth and creamy.
Once the meatloaf cupcakes are done, remove them from the oven and let them cool slightly. Top each cupcake with a generous dollop of cheesy mashed potatoes and sprinkle with shredded cheddar cheese.
Return to the oven for an additional 5 minutes, or until the cheese is melted and bubbly.