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 water, a little at a time, and knead until a smooth dough forms.
Cover the dough with a damp cloth and let it rest for about 30 minutes.
Place the cubed potatoes in a pot of salted water and bring to a boil. Cook until the potatoes are tender, about 10-15 minutes.
Drain the potatoes and mash them until smooth.
In a skillet, heat a small amount of oil over medium heat. Add the finely chopped onion and sauté until translucent.
Stir in the minced garlic, ground cumin, ground turmeric, and garam masala. Cook for another minute.
Add the mashed potatoes to the skillet and mix well to combine with the spices. Season with salt and black pepper to taste.
Remove from heat and let the filling cool. Stir in chopped fresh cilantro if desired.
Divide the dough into small balls and roll each ball into a thin circle, about 6 inches (15 cm) in diameter.
Place a spoonful of the potato filling in the center of each dough circle.
Fold the dough over the filling to form a semi-circle and press the edges together to seal. Use a fork to crimp the edges for a secure seal.
Heat vegetable oil in a deep frying pan over medium heat.
Carefully place the aloo pies into the hot oil and fry until golden brown and crispy, about 2-3 minutes per side.
Use a slotted spoon to remove the pies from the oil and place them on a paper towel to drain excess oil.
Enjoy your meal!