Begin by preheating your oven to 350°F (175°C), ensuring it is fully heated before baking.
In a large mixing bowl, combine the ground meat, breadcrumbs, grated Parmesan, finely chopped onion, minced garlic, egg, milk, Worcestershire sauce, diced bell peppers, oregano, and a generous pinch of salt and pepper. Mix the ingredients thoroughly using your hands or a wooden spoon until everything is well incorporated.
Shape the meat mixture into a uniform loaf approximately 2 inches thick and transfer it to a lined or greased baking dish for easy cleanup.
In a separate small bowl, prepare the glaze by whisking together the ketchup, brown sugar, Dijon mustard, and apple cider vinegar until smooth and well combined.
With a spatula, spread half of the prepared glaze evenly over the top and sides of the meatloaf, ensuring it is generously coated.
Bake in the preheated oven for about 50-60 minutes, or until the internal temperature of the meatloaf reaches a safe 160°F (70°C) as measured with a meat thermometer.
Approximately 10 minutes before cooking is complete, brush the remaining glaze over the top of the meatloaf to create an enticing sticky finish.
Once the meatloaf is fully cooked, remove it from the oven and allow it to rest for about 10 minutes before slicing. This resting period will help it retain its juices.
Notes
Serve with creamy mashed potatoes and steamed broccoli for a complete meal.