Heat the oven to 375 degrees F and line a baking sheet with parchment paper.
Place the ground beef, spinach, artichoke hearts, breadcrumbs, egg, garlic, oregano, salt, and pepper in a large bowl. Mix gently with your hands until the ingredients are evenly combined.
Divide the mixture into four equal portions. Flatten each portion slightly and press one Fontina cube into the center, then shape the meat around the cheese to seal it completely.
Arrange the formed meatloaves on the prepared baking sheet with space between them.
Bake for 25 to 30 minutes until the internal temperature reaches 160 degrees F and the cheese inside feels soft when pressed lightly.