Put the flour, baking powder, salt and yogurt in a large mixing bowl. Wash your hands well and dry thoroughly.
Mix the ingredients together by hand and knead till a smooth dough is formed. Cover with cling film and keep in a warm place for 5-6 hours at least.
After 5-6 hours, the dough will have risen and become fluffy. Remove the cling film and punch the dough to remove extra air from it. Knead again till the dough is smooth and elastic.
Divide the dough into several equal-sized balls.
Set up the cooking oil to heat, in a large, deep pan, on medium heat. Also prepare a plate or large bowl to place the cooked Bhaturas for draining, by lining it with paper towels.
Lightly flour a clean, dry rolling surface and place one ball on it. Roll out into a circular shape of 6" diameter. You could also roll the ball into a long oval shape of the same size.
To test if the oil is hot, drop a small ball of dough into it. If the ball quickly rises to the surface oil the oil and sizzles, the oil is ready.
Once the oil has reached the correct temperature, add a rolled-out Bhatura to it gently, to avoid splashing hot oil. In 5-7 seconds, turn gently with a slotted spoon.
Wait another 5-7 seconds and press gently in the center of the Bhatura with the slotted spoon. This will cause tit to puff up like a ball! Keep frying and turning gently till both sides are golden.
Drain and remove from oil when done and keep in bowl/ plate on paper towels.