The recipe makes about 24.
750g (11/21b) sausage mince
1 large onion
1/4 teaspoon mixed herbs
4 thick slices white bread
2 x 375g (12oz) pkts puff pastry
1 tablespoon cold water
1. Put sausage mince, peeled and grated onion, mixed herbs, salt and pepper into bowl. Cut crusts from bread, put bread in separate bowl. Pour over enough warm water to cover, let bread stand 5 minutes. Drain off water, squeeze bread gently to extract water. Add bread to sausage mince mixture; mix well. (Bread absorbs any excess fat in the sausage mince and helps to prevent meat shrinking inside pastry when cooking.)
2. With pastry at room temperature, cut each packet of puff pastry in half. Roll out each piece of pastry to 30cm (12in) square. Trim edges of each piece of pastry on three sides leaving one side untrimmed. This untrimmed side will be cut off later when rolling sausage rolls.
3. Fill meat mixture into large piping bag that does not have piping nozzle attached. Pipe meat along edge of pastry, leaving untrimmed edge of pastry at opposite end of meat.
4. Turn edge of pastry over filling, then turn again so that filling is completely enclosed in pastry. Cut along edge of pastry with sharp knife. Repeat with remaining filling and pastry.
5. With back of knife, flatten rolls slightly at 1cm (1/2 inch) intervals. Brush rolls with combined cold water and egg-yolk. Cut rolls into 5cm (tin) pieces. Use first roll as guide for size of remaining rolls.
6. Put rolls on greased oven tray, side by side, just lightly touching as shown in picture. Bake in hot oven 10 minutes, reduce heat to moderate, cook further 15 minutes.