Preheat your oven to 375°F.
Heat 2 tsp olive oil in a skillet. Add the Hatfield Pork and brown it on all sides.
Remove from the pan and let it cool for at least 15 minutes. This is a crucial step to prevent the puff pastry from getting soggy.
Roll out your thawed puff pastry sheet on a lightly floured surface. Using a pizza cutter or a knife, cut the sheet into long, thin strips, about ½-inch wide.
Take the cooled pork loin and start wrapping the pastry strips around it, just like a mummy's bandages. Leave some small gaps so you can see the pork underneath. Don't worry about being too neat—the messy look adds to the mummy's charm! Make sure to tuck the ends of the pastry strips underneath the pork loin.
Add two slices of mozzarella and two sliced olives for eyes.
Brush the entire puff pastry-wrapped pork loin with the beaten egg. This will give it a beautiful golden-brown color and a glossy finish.
Place the mummy on a parchment-lined baking sheet and bake for about 15-20 minutes, or until the puff pastry is puffed and golden brown and the internal temperature of the pork reaches 145°F.