Preheat oven to 400°F. Lightly oil a 12-cup muffin tin with the neutral oil.
Stir together the glaze: ketchup, brown sugar, vinegar, and hot sauce. Set aside.
In a large bowl, combine breadcrumbs, milk, onion, garlic, parsley, salt, and pepper.
Whisk in the beaten egg, ketchup, Worcestershire, and Dijon until evenly moistened.
Add ground beef and gently mix with your hands just until combined; do not overwork.
Divide mixture among muffin cups, packing lightly. You should fill all 12 wells evenly.
Spoon a little glaze over each mini meatloaf, spreading to coat the tops.
Bake 20–22 minutes, until centers reach 160°F. Rest 5 minutes, then loosen edges and lift out.
For stickier tops, broil 1–2 minutes after baking, watching closely.