01 - Preheat oven to 350°F. Line a loaf pan with parchment paper or lightly grease the surface.
02 - In a skillet over medium heat, cook the sliced leeks and chopped onion in a small amount of oil for about 4 to 5 minutes until tender. Add minced garlic and continue cooking for 1 minute. Remove from heat and allow the mixture to cool slightly.
03 - In a large mixing bowl, blend ground meat, eggs, breadcrumbs, milk, parsley, salt, pepper, thyme, and smoked paprika. Integrate the cooled vegetable mixture and mix gently just until incorporated.
04 - Transfer the meat mixture into the prepared loaf pan, gently patting to form an even layer.
05 - In a separate small bowl, combine ketchup and Worcestershire sauce, then spread evenly over the surface of the meat mixture.
06 - Place the pan in the oven and bake for 55 to 60 minutes, or until the center registers 160°F and the top is caramelized.
07 - Allow to rest in the pan for 10 minutes before slicing. Serve warm.