Mix water,sugar,salt,yeast in a bowl and whisk together. Add flour and mix together in bowl.
Cover loosely and leave to rise 2 hours.
Sprinkle flour over risen dough and turn out onto a sheet of wax paper.
Sprinkle top of dough with flour and shape into a loaf.
Lower bread and wax paper into slow cooker.
Set slow cooker on high and set it for 2 hours.
When bread is cooked remove from slow cooker and place on wire rack to cool and butter top of bread with butter.Cool completely before slicing.