Preheat oven to 350 degrees F. Line a 9x5-inch loaf pan with parchment paper or lightly grease it with oil. Set aside.
In a large bowl, combine the ground beef, onion, breadcrumbs, garlic, Italian seasoning, parsley, paprika, ketchup, eggs, milk (or ketchup), bouillon powder, salt, and pepper.
Gently mix with your hands or a spoon until just combined. Avoid overmixing to keeps the meatloaf soft and juicy.
Shape the seasoned meat into a loaf and gently lift it into the prepared loaf pan.
In a small bowl, stir together the ketchup, apple cider vinegar, and honey (or brown sugar) until smooth.
Spread half of the sauce evenly over the meatloaf. Reserve the remaining for later.
Bake uncovered for 45 minutes. Remove from the oven, spread the remaining sauce over the top, and bake for another 15–20 minutes, or until the internal temperature reaches 160°F (71°C).
Let the meatloaf rest for 10 minutes before slicing.