Line a 7-quart crockpot with aluminum foil, and lightly spray with nonstick spray. Set it aside.
Using a large mixing bowl, add the ground beef, finely diced onion, the plain bread crumbs and the panko bread crumbs, ketchup, eggs, Worcestershire sauce, heavy cream, Italian seasoning, kosher salt, and black pepper.
To mix the meatloaf together, you can either use a large wooden spoon or your hands. If you are using your hands, please be sure to wear disposable gloves for safety. Mix all the ingredients until well combined.
Transfer the meat mixture into the prepared crockpot. Carefully and tightly shape the meatloaf into an oblong shape.
In a small mixing bowl, combine the glaze ingredients and stir until well combined. Using a basting brush, evenly spread the glaze on the top of the meatloaf.
Set the crockpot to 4 hours on high. Any leftovers can be stored in an airtight container in the refrigerator for up to 1 week.