Preheat your oven to 350°F (175°C). This ensures the meatloaf cooks evenly.

In a large mixing bowl, combine the ground beef, breadcrumbs, egg, diced onion, minced garlic, Worcestershire sauce, ketchup, mustard, salt, black pepper, and dried thyme. Use your hands or a mixing spoon to blend the ingredients until just combined. Be careful not to overmix, as this can make the meatloaf tough.

Transfer the meat mixture into a loaf pan, pressing it down gently to form a loaf shape. Alternatively, you can shape it by hand and place it on a baking sheet lined with parchment paper.

In a separate small bowl, mix together the ketchup, brown sugar, and apple cider vinegar to create the glaze.

Spread half of the glaze over the top of the meatloaf, reserving the rest for later.

Place the loaf pan in the preheated oven and bake for 45 minutes.

After 45 minutes, remove the meatloaf from the oven and spread the remaining glaze on top. Return it to the oven for an additional 15 minutes, or until the internal temperature reaches 160°F (70°C).

Once cooked, remove the meatloaf from the oven and let it rest for 10 minutes before slicing. This allows the juices to redistribute, making for a moister meatloaf.

Slice and serve warm, ideally with mashed potatoes and steamed vegetables.