01 - Preheat oven to 375°F and prepare a loaf pan by lining it with parchment paper or lightly greasing.
02 - In a large bowl, mix ground turkey, breadcrumbs, onion, garlic, eggs, milk, ketchup, Worcestershire sauce, thyme, salt, and pepper until just combined without overmixing.
03 - Transfer mixture into the prepared loaf pan, pressing gently to even out the surface.
04 - Combine ketchup, brown sugar, and Dijon mustard in a small bowl; spread evenly over meatloaf.
05 - Bake for 55 to 60 minutes until the internal temperature reaches 165°F; let rest 10 minutes before slicing.
06 - Place peeled and cubed potatoes in a pot, cover with cold salted water, bring to a boil, and cook until fork-tender, about 15 to 18 minutes.
07 - Drain potatoes, return to pot; add warmed milk and butter, mash until creamy, then season with salt and pepper to taste.
08 - Slice meatloaf and serve with mashed potatoes, garnishing with chopped chives if desired.