01 -
Preheat your oven to 350°F (175°C).
02 -
In a skillet over medium heat, melt the butter and sauté the thinly sliced onions until they are caramelized and golden brown, about 20-25 minutes. Add a splash of beef broth to deglaze the pan and stir until the liquid is absorbed. Set aside to cool.
03 -
In a large bowl, combine the ground beef, breadcrumbs, milk, minced garlic, beaten egg, Worcestershire sauce, Dijon mustard, dried thyme, salt, and pepper. Mix until well blended.
04 -
Fold in the caramelized onions and half of the shredded Gruyère cheese. Shape the mixture into a loaf and place it in a baking dish.
05 -
Bake in the preheated oven for 1 hour or until the internal temperature reaches 160°F (70°C).
06 -
Sprinkle the remaining shredded Gruyère cheese over the top of the meatloaf and bake for an additional 5-10 minutes until the cheese is melted and bubbly.
07 -
Allow the meatloaf to rest for 10 minutes before slicing. Serve with your favorite sides.