In a large bowl, combine the flour, baking powder, and salt.
Add the vegetable oil and mix until the mixture resembles coarse crumbs.
Gradually add the warm water, mixing until a soft dough forms. The dough should be soft but not sticky.
Knead the dough for about 5 minutes until smooth.
Cover the dough with a damp cloth and let it rest for at least 30 minutes.
If making stuffed roti, such as Dhal Puri or Aloo Roti, prepare the filling.
In a bowl, combine the cooked and mashed split peas or potatoes, minced garlic, ground cumin, ground turmeric, salt, and black pepper. Mix well and set aside.
Divide the dough into small balls (about the size of a golf ball) if making plain roti, or larger balls if making stuffed roti.
On a lightly floured surface, roll each ball into a flat circle about 1/4 inch (0.6 cm) thick.
If making stuffed roti, place a spoonful of the filling in the center of each rolled dough circle.
Fold the edges of the dough over the filling to enclose it completely, then gently flatten and roll out the filled dough into a flat circle again.
Heat a small amount of vegetable oil in a large skillet or griddle over medium heat.
Place the rolled dough onto the hot skillet and cook until bubbles form on the surface and the bottom is golden brown, about 1-2 minutes.
Flip the roti and cook the other side until golden brown, about 1-2 minutes more.
Repeat with the remaining dough and filling (if using), adding more oil to the skillet as needed.
Enjoy your meal!