Preheat oven to 400°F (200°C). Line a large sheet pan with parchment paper or foil.
Prepare the potatoes: In a bowl, toss the halved potatoes with olive oil, salt, pepper, garlic powder, and paprika. Spread them on one side of the sheet pan, cut side down.
Make the meatloaf mixture: In another bowl, mix together ground beef, breadcrumbs, milk, egg, onion, garlic, ketchup, Worcestershire sauce, mustard, salt, and pepper until well combined. Shape into 4–6 small loaves and place them on the other half of the sheet pan.
Add glaze: Mix the ketchup, brown sugar, and vinegar in a small bowl. Brush over each mini meatloaf.
Bake: Place the sheet pan in the oven and bake for 25–30 minutes, or until the meatloaves are cooked through (internal temp 160°F / 70°C) and the potatoes are golden and tender.
Optional: During the last 10 minutes, you can add green beans or broccoli on the pan tossed with olive oil, salt, and pepper.
Serve: Garnish with chopped parsley and serve hot with the roasted potatoes and vegetables.
