Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper or lightly grease a loaf pan.

In a medium skillet over medium heat, melt the butter. Add the diced onions and sauté for 5-6 minutes until translucent and soft. Add minced garlic and cook for an additional 1 minute until fragrant. Remove from heat and let cool slightly.

In a large mixing bowl, combine the ground beef, sautéed onions and garlic, eggs, milk, breadcrumbs, Worcestershire sauce, thyme, oregano, salt, pepper, and parsley. Mix gently with your hands until just combined - do not overmix or your meatloaf will become dense.

Transfer the meat mixture to your prepared baking sheet and shape it into a loaf approximately 9 inches long and 5 inches wide, or press evenly into your loaf pan.

In a small bowl, whisk together all glaze ingredients until smooth.

Spread half of the glaze evenly over the top and sides of the meatloaf.

Bake in the preheated oven for 40 minutes, then remove and carefully spread the remaining glaze over the top.

Return to the oven and bake for an additional 15-20 minutes, or until an instant-read thermometer inserted into the center registers 160°F (71°C).

Allow the meatloaf to rest for 10 minutes before slicing. This resting period is crucial for the juices to redistribute throughout the meat.

Slice into thick portions and serve warm with your favorite sides.