Mix the egg and milk together in a large bowl.
Add bread cubes and let stand for 15 minutes.
Mash the soaked bread with a fork.
Mix in mustard, herbs, spices, onion, celery, and bacon lardons.
Incorporate the beef, pork, and Worcestershire sauce.
Chill the covered mixture in the fridge for at least 2 hours.
Preheat the oven to 180°C.
Transfer the mixture to a 30cm x 11cm loaf tin.
Cover the top with streaky bacon slices.
Bake for 55 minutes until cooked through.
Let the meatloaf rest for 5 minutes before slicing.
Mash cooked potatoes with butter over low heat and season.
Serve meatloaf slices with mashed potato and gravy.