In a large mixing bowl, combine the flour, salt, and sugar (if using).
Add the vegetable oil or melted butter and mix well.
Gradually add the warm water, mixing until a soft dough forms. If the dough is too dry, add a little more water, a tablespoon at a time.
Knead the dough on a lightly floured surface for about 5-7 minutes, or until it is smooth and elastic.
Cover the dough with a damp cloth and let it rest for at least 30 minutes. This helps to relax the gluten and makes the dough easier to roll out.
Divide the dough into small balls, about the size of a golf ball.
On a lightly floured surface, roll each ball into a thin circle, about 6-8 inches (15-20 cm) in diameter. Dust with additional flour as needed to prevent sticking.
Heat a non-stick skillet or griddle over medium heat.
Place a rolled-out dough circle onto the hot skillet.
Cook for about 1-2 minutes, or until bubbles start to form on the surface and the bottom is golden brown.
Flip the chapati and cook the other side for another 1-2 minutes.
Brush the cooked chapati with a little oil or melted butter, if desired.
Repeat with the remaining dough balls, stacking the cooked chapatis on a plate and covering them with a clean cloth to keep them warm.
Enjoy your meal!