Start by grabbing a large mixing bowl. Add the ground beef, breadcrumbs, milk, egg, French onion soup mix, caramelized onions, garlic, dried thyme, salt, and pepper. Gently mix it all together. You want it combined but not overly mixed, or the meatloaf could become tough. Once everything looks evenly incorporated, fold in the shredded Swiss cheese for bursts of gooey flavor in every bite.

Take the meat mixture and form it into a loaf shape. Gently place it in your crockpot. To make removal simple, consider lining it with parchment paper or using a loaf pan that fits your crockpot.

Cover the crockpot and set it to cook on low for about 6 hours. This slow cooking method ensures every ingredient melds beautifully, resulting in a juicy and flavorful loaf. Check for doneness using a meat thermometer; the internal temperature should reach 160°F (71°C).

Fifteen minutes before the meatloaf finishes cooking, lay Swiss cheese slices on top. Cover the crockpot again and allow the cheese to melt into a rich, velvety layer. This step takes the meatloaf from delicious to irresistible.

Carefully transfer the meatloaf from the crockpot to a serving plate. Sprinkle fresh parsley on top for a burst of color and serve thick slices alongside your favorite sides. Every bite oozes with cheesy, French onion-inspired goodness!