1. Preheat your oven to 375°F (190°C). Line a baking sheet with parchment paper or foil.

2. In a large mixing bowl, combine the ground beef, breadcrumbs, egg, milk, chopped onion, garlic, ketchup, Worcestershire sauce, thyme, paprika, salt, and pepper. Mix gently until well combined.

3. Shape the mixture into a loaf shape and place it on the prepared baking sheet.

4. Bake for 50–60 minutes or until the internal temperature reaches 160°F (70°C). Let it rest for 5–10 minutes before slicing.

Prepare the Caramelized Onion Gravy:

1. Heat butter and olive oil in a skillet over medium heat. Add the sliced onions and cook, stirring occasionally, until golden brown and caramelized (about 20–25 minutes).