Heat the oil in a large saucepan on a medium to high heat. Add the duck legs and brown on all sides for about 10 minutes. Remove to a plate and set aside.

Carefully lift the duck legs out of the sauce and place on a plate – they will be very tender so try not to lose any of the meat. Pull off and discard the skin, then shred the meat with 2 forks and discard the bones. Season the meat with salt and freshly ground black pepper, then add it back into the stock and onions, along with the chunks of black pudding. Stir to mix, then strain through a fine sieve and discard the stock.

Roll the mixture into 2 sausage shapes (the length of the pastry), wrap each long sausage in cling film then refrigerate for 30 minutes.

Meanwhile, heat oven to 200C/fan 180C/gas 6. Line a baking tray with baking paper.

Remove the duck and black pudding sausages from the fridge, unwrap and discard the cling film. Unroll the pastry onto a board and cut in half lengthways. Place a sausage along the length of each pastry strip, leaving a 1cm edge. Brush the edges with beaten egg and tightly roll the pastry around the mixture.

Use a sharp knife to cut each roll into approx. 8 to 10 pieces, and place on the baking tray lined with baking paper.

Prick each sausage roll a couple of times with a fork, or use a sharp knife to cut small slits in them, and then brush with the rest of the beaten egg.

Place in the oven and cook for 30 minutes (turn the tray after 15 minutes so that they cook evenly) until the pastry is puffed and crisp and the meat has cooked through. Remove and place on a wire rack - eat hot or cold.