Pre-heat oven 200C. Line 2 baking trays with baking paper.
First peel and cook potatoes for 15-20 minutes or until cooked. Mash potatoes with butter and little milk, set aside to cool completely.
Put sausage meat in a bowl with the chopped onion, crushed garlic, mashed potato, season with salt & pepper. Mix into a long sausage.
You can make your own puff pastry or use store brought.
Roll out pastry on a floured surface, roll to ½ cm thickness. Cut out 4 inch lengths of the pastry, put sausage mix along the edge of the pastry, wet the edge of the pastry with water. Roll pastry to enclose the meat with the sealed end underneath. Prick pastry on top with a fork. Brush with egg wash. Cut pastry into about 6-8 pieces.
Put sausage rolls onto prepared tray lined with baking paper. Bake for 30 minutes or until a light golden colour. Serve with tomato sauce.