Preheat oven to 400°F.
Cook onion and garlic in oil in a 12-inch skillet over moderate heat for a couple minutes then add the carrot. Cook until the carrot is starting to soften then add the mushrooms and 1/2 of the salt and pepper. The mushrooms will release liquid and cook until it has evaporated. Stir in Worcestershire sauce, parsley, and 3 tablespoons ketchup, then transfer vegetables to a large mixing bowl.
Stir together bread crumbs and milk in a small bowl and let stand 5 minutes. Stir in egg and egg white, then add to vegetables. Add turkey and remaining salt and pepper to vegetable mixture and mix well with your hands. Or, you can use a kitchen tool. This is one of my favorites ---- don't have a name for it but it looks sort of like a mini rug beater. (Mixture will be very moist.)
Here's where I went wrong a little. You are supposed to shape the mixture into an oval on a baking sheet about 9" long by
Allegedly the meatloaf was supposed to take 50-55 minutes to reach an internal temperature of 170 degrees as measured by a meat thermometer. That may have been the case if the meatloaf was thick enough but my thinner version reached the target temp in only 25 minutes. Then I went through the trauma of not knowing if I had inserted the thermometer too close to the baking sheet giving me a false reading. 25 minutes felt too short so I empirically added another 10 minutes or so and resorted to the tried and proven fork method ( see evidence here).
The meatloaf was great though a 1/2 cup of parsley doesn't really count as a serving of vegetables. So I cooked up some kale, garlic, and crushed red chilies.