Heat the oven to 350°F: Set the oven to pre-heat and place a rack in the bottom third of the oven. Line a baking sheet or other baking dish with aluminum foil.

Soak the bread pieces in the milk: Combine the bread pieces and the milk in a small bowl. Let stand until the bread has broken down into a thick porridge, occasionally stirring and mushing the bread against the sides of the bowl. You can leave the crusts on the bread or trim them off before soaking; if you leave them on, remove any large pieces that haven’t broken down after soaking.

Cook the veggies: Warm a few teaspoons of olive oil in a skillet over medium heat. Add the diced onions, carrots, and celery. Cook until the onions are translucent and the carrots have softened, 6 to 8 minutes. If the vegetables begin to brown, turn down the heat. Add the garlic and stir until fragrant, about 30 seconds. Add the thyme and tomato paste, and stir until coated. Remove from heat and let cool slightly.

Make the meatloaf mix: In a large mixing bowl, combine the ground meat, beaten eggs, Worcestershire sauce, salt and pepper, soaked bread and milk, and the cooked vegetables. Use your hands to work the ingredients together until just combined.

Shape the loaf: Transfer the meatloaf mixture to your foil-lined baking sheet or baking dish. Shape it into a loaf roughly 9 inches by 5 inches. (If using a loaf pan, just pat the meatloaf mixture into the pan.)