Preheat a smoker to 250°F. Set out a sheet of parchment paper on a work surface for shaping the meatloaf.

In a large bowl, combine the ground beef, egg, breadcrumbs, Parmesan, Italian seasoning, garlic powder, salt, and black pepper. Mix gently just until everything is evenly combined.

Shape the mixture into a rectangle about 1 inch thick on the parchment. Arrange the mozzarella cubes in a line down the center, leaving space at each end. Fold the meat mixture over the cheese and pinch the seams closed to seal it inside.

Lay the bacon slices side by side on the parchment, slightly overlapping them. Place the meatloaf seam-side down across the bacon, then wrap the bacon around it. Tuck the ends underneath.

Transfer the wrapped loaf to the smoker. Smoke until the center reaches 160°F on an instant-read thermometer, checking through the meat rather than the cheese.

Brush the top of the bacon with 1/4 cup marinara sauce. Continue smoking for about 10 minutes, until the sauce is warm and lightly set.

Carefully move the meatloaf to a cutting board and let it rest for 10 minutes. Spoon the remaining marinara over the top, sprinkle with parsley, and slice to serve.