1. Preheat oven: Preheat the oven to 375°F (190°C). Line a baking sheet with parchment or lightly grease a loaf pan (9×5 inches) if you prefer a uniform shape.
2. Soak the breadcrumbs: In a small bowl, combine the breadcrumbs and milk. Let sit for 5 minutes so the crumbs absorb the milk and become a binder.
3. Sauté aromatics (optional): In a small skillet, heat 2 tablespoons olive oil over medium heat. Sauté the chopped onion (and grated carrot, if using) for 3–4 minutes until softened and slightly translucent. Add the garlic for the last 30 seconds. Remove from heat and let cool slightly. (This step mellows the onion and prevents raw onion bites.)
4. Mix the meatloaf: In a large bowl, combine the ground meat, soaked breadcrumbs, beaten eggs, cooled sautéed aromatics (or raw if you skipped step 3), parsley, Worcestershire sauce, Dijon, salt, pepper, and dried herbs. Gently mix with your hands or a fork until just combined — avoid overworking, which makes the loaf dense.
5. Shape the loaf: Transfer the mixture to the prepared loaf pan or form into a compact loaf on the lined baking sheet. Smooth the top with wet hands.
6. Prepare the glaze: In a small bowl, whisk together ketchup, brown sugar, vinegar, and Dijon. Spread about two‑thirds of the glaze evenly over the top of the meatloaf. Reserve the rest for serving or to brush during the last few minutes of baking.
7. Bake: Place the meatloaf in the preheated oven. Bake for 45–55 minutes (in a loaf pan it may take a bit longer), or until an instant‑read thermometer inserted into the center reads 160°F (71°C). If using the reserved glaze, brush it on during the last 10 minutes of baking for a glossy finish.
8. Rest: Remove the meatloaf from the oven and let it rest 10–15 minutes before slicing. Resting helps the loaf hold together and keeps it juicy.
9. Slice and serve: Slice into thick slices and serve with extra glaze on the side. Great with mashed potatoes, roasted vegetables, or a simple green salad.
10. Store: Refrigerate leftovers in an airtight container for 3–4 days; reheat in the oven at 300°F (150°C) until warmed through. Meatloaf also freezes well—slice first, freeze between sheets of parchment, then store in a freezer bag up to 3 months.

Tips

• For leaner meat, add a tablespoon of olive oil or 1/4 cup grated zucchini to keep moisture.
• If you prefer a smokier glaze, substitute half the ketchup with barbecue sauce.
• To test doneness without a thermometer, the juices should run clear and the center feel firm but springy.

Comforting, easy, and endlessly adaptable — this meatloaf is weeknight magic with leftovers that make excellent sandwiches.