Rub the butter into the flour garlic powder and salt. Warm the milk, water and sugar and crumble in the yeast and dissolve. Mix the potato into the flour, make a well, add the watery yeast mixture. Mix in and knead really well until very elastic.

Cover and leave to prove to double its size. Knock back cut into desired sized pieces and place on baking tray
Cover and prove to double its size again. 

Dust each roll with flour then bake at 220 for about 15 mins.