Preheat your oven to 240C/220 Fan/Gas Mark 5 with a baking tray on the middle shelf.
If needed, finely score the pork belly. Dry with a paper towel, rub the skin all over with lemon juice, and then season with salt.
Place in the oven skin side up and roast for 25 minutes until the skin starts to crackle.
Reduce the oven to 160C/150 Fan/Gas Mark 3 and cook for a further 1 1/2 hours until the meat is cooked through but tender. Remove from the oven and make sure to rest for 10 minutes before slicing and serving.
Step 2 : Cook the potatoes
When the pork has nearly finished cooking you can start the potatoes.
Place your potatoes in a large pot and cover with cold water. Then simply turn the heat up and boil for 20 minutes until tender. Drain and set aside.
Step 3 : Cook the sauce
Melt the butter in a small pot in order to make the parsley sauce. When the butter has melted, stir in the flour until fully combined.
Then add the milk slowly while stirring. Keep on the heat for another 3 or 4 minutes until the sauce thickens. Add the parsely, milk, and nutmeg and stir thoroughly. Taste test and add salt and pepper as needed.
Step 4 : Serve
Serve the pork belly cut into strips and the parsley sauce drizzled over the potatoes.