Preheat your oven to 350°F (175°C).

In a medium skillet, cook the diced bacon over medium heat until crispy, stirring occasionally. Remove the bacon with a slotted spoon, setting aside 1 tablespoon for later. Drain off excess fat, leaving 1 tablespoon in the pan.

Add the chopped onion and mushrooms to the skillet. Sauté until soft and tender, then remove from heat.

In a large mixing bowl, combine the ground beef, egg, and evaporated milk. Stir in the cooked onions and mushrooms. Mix in about 4 ounces of the shredded Swiss cheese and all the cooked bacon except the reserved tablespoon.

Gradually fold in the crushed cornflakes until the mixture is well combined. Shape the meat mixture into a loaf and place it into a loaf pan.

Bake the meatloaf in the preheated oven for about 1 hour. Once cooked, drain any excess grease. Sprinkle the remaining 2 ounces of Swiss cheese and the reserved tablespoon of bacon over the top. Return to the oven and bake for an additional 5 minutes, or until the cheese is fully melted.