In a large mixing bowl, combine 500 grams of whole wheat flour, 1 teaspoon of salt, 1 teaspoon of sugar, and 1 teaspoon of baking powder.
Add 200 grams of yogurt and 2 tablespoons of melted butter to the dry ingredients. Mix well.
Gradually add water (approximately 150 ml) and knead the dough until it becomes soft and pliable. Cover the dough with a damp cloth and let it rest for 30 minutes.
Preheat your tandoor oven or a regular oven to 250°C.
Divide the dough into 8 equal portions and roll each portion into a ball.
Flatten each ball and roll it out into a circular shape with a diameter of about 6-7 inches.
Apply water on one side of the rolled-out dough and place the wet side on the inner wall of the tandoor oven or on a baking tray if using a regular oven.
Cook the roti for 2-3 minutes in the tandoor oven or 5-7 minutes in a regular oven until it puffs up and turns golden brown.
Remove the roti from the oven using tongs and immediately apply a generous amount of melted butter on top.