Preheat your oven to 375°F (190°C). Line a 10 x 5 inch loaf pan with parchment paper and spray with nonstick cooking spray.

Combine ketchup, apple cider vinegar, mustard powder, brown sugar, Worcestershire sauce, and pepper in a saucepan over medium heat and let simmer for about 5 minutes until thickened.

In a large mixing bowl, combine breadcrumbs, eggs, and milk (or half and half). Let it soak for about 10 minutes.

Melt butter in a skillet over medium heat. Add diced yellow onion and sauté for 4–5 minutes until golden brown, then add minced garlic and sauté an additional 2–3 minutes.

In the bowl with the soaked breadcrumbs, combine sautéed onion and garlic, along with chopped parsley, paprika, marjoram, sage, Worcestershire sauce, and ground turkey. Gently mix all ingredients.

Transfer the turkey mixture into the prepared loaf pan, pressing down gently. Spread half of the prepared glaze on top.

Bake for 40–45 minutes until the internal temperature reaches 160°F (71°C). Let rest for 30 minutes before slicing.