1-Melt 1 tablespoon of butter in a medium skillet over medium-high heat and add the sliced onion. Caramelize the onions for about 10 minutes, stirring occasionally and lowering heat if needed to prevent burning.

2-Place the caramelized onions at the bottom of a 5-6 quart slow cooker.

3-In a large bowl, mix 2 pounds of lean ground beef with 1 envelope of beefy onion soup mix, 3/4 cup Italian bread crumbs, 2 large eggs, 3/4 cup milk, and 1 tablespoon Worcestershire sauce.

4-Dice 5 slices of Swiss cheese and add them to the meat mixture. Combine thoroughly.

5-Shape the mixture into a loaf using clean hands and place it on top of the onions in the slow cooker.

6-Pour the can of French onion soup evenly over the meatloaf.

7-Cover and cook on low for 5-6 hours or on high for 3 hours, until the internal temperature reaches 165°F (74°C).

8-About 5 minutes before serving, top the meatloaf with the remaining 3 slices of Swiss cheese, cover, and allow the cheese to melt.

9-Optionally garnish with chopped parsley before slicing and serving. For extra flavor, spoon some of the cooking juices over individual slices.