1. Mix the flour and salt. Add 75ml sunflower oil and beat with a hand blender until the mixture resembles fine breadcrumbs.
2. Stir in 750-800 ml boiling water with a wooden spoon. Once mixed, use your hands to shape the dough into a ball. Turn out onto a lightly floured surface and knead for about five minutes, until the dough is soft and pliable. Cover with cling film and set aside to rest for about half an hour.
3. Roll out the dough into a long rope shape and cut into 17 individual pieces. Roll each piece into a ball.
4. Roll one of the balls into a thin oblong shape. Put 250 ml of the butter into a bowl and use a palette knife to spread a thin layer of soft butter over the surface of the dough.
5. Mix the self-raising flour and baking powder and place in a flour dredger.
Sprinkle a thin layer of flour over the butter.
6. Starting at one of the bottom corners of the dough, twist the dough around to make a thin rope shape.
7. Twist the rope shape around in a spiral to form a round shape. Repeat with each ball of dough.
8. Roll out each spiral roll onto a lightly floured surface to form a flat disc. If you want a perfectly round shape, use a bowl or pot lid to press a circle out of the rolled-out dough.
9. Heat the remaining oil and butter until the butter has melted. Heat a heavy-based pan over medium heat on the stove. Once hot, add one of the rotis. Cook until you see bubbles starting to form on the surface. Turn the roti over and brush with the oil mixture. Turn it again and brush the other side. Once both sides of the roti are golden, remove from the pan and repeat with the remaining dough.