Preheat the oven to 350 degrees and lightly grease a loaf pan.
In a large bowl, combine the ground beef, 3/4 cup of the shredded Pepper Jack cheese, breadcrumbs, egg, milk, diced onion, salt, and black pepper.
Mix with clean hands until the ingredients are evenly distributed but not overworked.
Transfer the mixture to the prepared loaf pan and press it into an even shape.
Bake for 50 minutes, then sprinkle the remaining 1/4 cup of shredded Pepper Jack cheese over the top.
Return the pan to the oven and bake 10 more minutes until the cheese melts and the internal temperature reaches 160 degrees.
Let the meatloaf rest 5 minutes before slicing.