You can tweak it to your liking: I did, best I ever made.

Smoked Cast Iron Meatloaf
Ingredients
2 lb ground beef, preferably 80/20
2 eggs
3/4 cup bread crumbs, crushed crackers, or quick oats
1/2 cup milk
1 small onion, finely chopped
2–3 cloves garlic, minced
or 1 tsp garlic powder
2 tbsp Worcestershire sauce
1/4 cup ketchup or BBQ sauce
1 1/2 tsp salt
1 tsp black pepper
1 tsp paprika
1–2 tbsp bacon grease, optional
Extra bacon grease to coat skillet
Glaze
1/2 cup ketchup
2 tbsp brown sugar
1 tbsp mustard
Splash of Worcestershire sauce, optional
Instructions
Mix eggs, milk, bread crumbs, Worcestershire, ketchup, onion, garlic, salt, pepper, paprika, and optional bacon grease.
Add ground beef and mix gently. Do not overmix.
Coat cast iron skillet with a thin layer of bacon grease.
Form meatloaf into a loaf in the skillet, leaving about 1 inch space around the sides.
Smoke at 300–325°F using maple plus one small hickory chunk.
Cook until center reaches 145°F, then brush on glaze.
Continue cooking until center reaches 160°F internal.
Rest 10 minutes before slicing.