01 - Preheat oven to 350°F. Line a loaf pan with parchment paper or lightly grease with cooking spray.
02 - In a large mixing bowl, combine breadcrumbs and milk; allow to soak for 2 minutes until breadcrumbs are softened. Add ground turkey, egg, onion, garlic, carrot, parsley, salt, black pepper, thyme, Worcestershire sauce, and ketchup. Mix gently until just combined, being careful not to overmix.
03 - Press the mixture evenly into the prepared loaf pan. Smooth the top surface with the back of a spoon to create an even finish.
04 - Bake for 55 to 60 minutes, or until the center reaches an internal temperature of 165°F and juices run clear when pierced. Remove from oven and allow to rest for 10 minutes before slicing.
05 - While the loaf bakes, melt butter in a medium saucepan over medium heat. Whisk in flour and cook for 1 to 2 minutes until lightly golden and fragrant. Gradually whisk in broth to prevent lumps. Add onion powder and garlic powder. Bring to a gentle simmer, whisking frequently, until thickened, approximately 5 minutes. Season with salt and black pepper to taste.
06 - Slice the rested turkey loaf and arrange on serving plates. Spoon warm gravy generously over each slice. Serve immediately.