Preheat your oven to 350°F.
Cook onions, garlic, and mushrooms in a skillet until the onions are translucent, about 8 minutes.
Let this mixture cool.
In a large bowl, combine ground beef, breadcrumbs, eggs, milk, and the cooled onion mixture.
Season with salt and pepper, then mix until everything is just combined.
Shape the meat mixture into a loaf and place it on a baking sheet or pan.
Lay bacon strips over the top, overlapping slightly, and tuck the ends underneath.
Bake in the preheated oven for 60-75 minutes.
The bacon should be crispy, and the internal temperature of the meatloaf should reach 160°F.
Let the meatloaf rest for about 10 minutes before slicing and serving.
It ensures the juices are evenly distributed.