Thoroughly clean and trim the lamb pluck.

Simmer the lamb pluck in water for around 2 hours until tender. Once cooked, dice or grate the pluck and set aside.

In a large mixing bowl, combine the diced/grated lamb pluck with coarse oatmeal, suet, chopped onions, black pepper, ground coriander, and mace. Mix well to create the haggis filling.

Stuff the haggis filling into the prepared ox bung casing or pudding basin, leaving room for expansion during cooking.

Securely tie off the casing at both ends to prevent spills.

Place the filled haggis in a large pot and cover with simmering water.

Cook for 1.5 to 2 hours, maintaining a gentle simmer and turning the haggis occasionally.

Ensure the haggis reaches an internal temperature of at least 74°C.

Once cooked, carefully remove the haggis from the pot.

Slice and serve the haggis alongside neeps (mashed swede) and tatties (mashed potatoes) for a traditional Scottish feast.