Sausage rolls with rosemary & sweet onion

Heat the oil in a medium saucepan over a medium heat. Add the onion and a pinch of salt; sweat for 5 minutes until soft. Add the rosemary and cook for 3-4 minutes, then add the vinegar and honey; stir for 1 minute until the vinegar has cooked off. Tip into a mixing bowl; set aside to cool.

Remove and discard the skin from the sausages and mix the meat with the onion and rosemary until combined. Lightly dust a work surface with flour and roll each pastry sheet to a thickness of 0.3cm, keeping it in a rectangle.

Shape 1⁄2 the sausage mixture into a long cylinder the length of the pastry and lay along the edge of 1 pastry sheet. Roll the pastry over the sausagemeat so it is fully encased, brushing a little egg along the edge where the pastry meets to seal it. Trim the excess pastry (see tip, below) and sit the sausage roll on a large plate or tray, seam-side down. Repeat with the second pastry sheet, then chill for 30 minutes.

Preheat the oven to 200oC, gas mark 6. Use a sharp knife to cut each sausage roll into 4 equal pieces. Place on a large parchment-lined baking tray, brush all over with egg and scatter with the nigella seeds. Bake for 25-30 minutes until the pastry is golden and the meat is fully cooked with clear juices and no pink meat. Serve warm or at room temperature with English mustard on the side, if liked.