1. Step 1: Preheat oven to 350°F (175°C). Lightly grease a 9×5-inch loaf pan or line a baking sheet with parchment paper.

2. Step 2: Heat a small amount of olive oil in a skillet over medium heat. Add the finely chopped yellow onion and green bell pepper. Sauté for 5-7 minutes until softened. Stir in minced garlic and cook for 1 minute. Remove from heat and cool slightly.

3. Step 3: In a large bowl, whisk together egg, milk, and Worcestershire sauce.

4. Step 4: Add panko breadcrumbs, Parmesan cheese, parsley, salt, and pepper to the wet mixture. Stir in the cooled sautéed vegetables. Mix until just combined.

5. Step 5: Add ground beef. Using your hands, gently mix until just combined. Do not overmix.

6. Step 6: Transfer mixture to the prepared loaf pan or shape into an oblong loaf on the parchment-lined baking sheet. Press gently to remove air pockets.

7. Step 7: In a small bowl, whisk together ketchup, brown sugar, and Dijon mustard for the glaze.

8. Step 8: Brush about half of the glaze over the meatloaf. Bake for 45 minutes.

9. Step 9: Remove from oven, brush with remaining glaze. Return to oven and bake for another 15-20 minutes, until internal temperature reaches 160°F (71°C).

10. Step 10: Let meatloaf rest in pan for at least 10 minutes before slicing. Slice and serve.