Preheat the Oven: Set your oven to 350°F (175°C) and prepare a 10×15-inch baking dish. Lightly grease the dish or line it with parchment paper to make cleanup easier.
Mix the Meatloaf Base: In a large bowl, combine the ground beef, bread crumbs, minced onion, beaten eggs, salt, and pepper. Mix gently with your hands or a spoon until the ingredients are just combined. Avoid overmixing — it can make the meatloaf dense instead of tender.
Shape the Meatloaf: For the pinwheel method, lay a large sheet of wax paper or parchment on your counter. Press the meat mixture into a flat rectangle, approximately 14×18 inches. Keep the thickness even so it cooks uniformly.
Add the Cheese: Evenly spread the shredded cheddar cheese over the surface of the meat mixture, leaving about a ¾-inch border around all edges. This keeps the cheese from spilling out during baking.
Roll and Seal: Starting from one long edge, gently roll the meat mixture into a tight log — just like rolling a jelly roll. Pinch the ends closed to seal in the cheese. Carefully transfer the rolled loaf into the prepared baking dish, seam side down.
Bake: Place the dish in the preheated oven and bake for about 1 hour, or until the center reaches 160°F (71°C) on a meat thermometer. Depending on your oven, it may be done sooner — check around 45 minutes for doneness.
Add the Glaze: If you’d like to top your meatloaf with a classic glaze, mix ketchup and mustard together to taste. Once the meatloaf is fully cooked, increase the oven temperature to 400°F (200°C). Brush the glaze evenly over the top and return to the oven for about 10 minutes, until caramelized and slightly sticky.
Rest and Slice: Remove the meatloaf from the oven and let it rest for about 10 minutes before slicing. This helps the juices redistribute and keeps the loaf moist and flavorful.
