Using a cheese grater, grate the potatoes and pat dry with kitchen paper to remove most of the moisture.
Grate the Bury Black Pudding and mix together with the potato and mustard in a bowl.
Heat a little oil in a frying pan and place a large round biscit cutter into the pan. Pack the cutter with half of the potato mixture (remove the ring once a neat shape is achieved) and fry until crisp. Flip to cook the other side of the hash brown.
Bring a pan of water to the boil and add a pinch of salt and the vinegar. Poach the eggs until cooked but still runny in the middle.
To serve place the crispy hash brown on a plate and top with the poached egg and add a twist of ground black pepper.