In a large bowl, combine the flour, salt, sugar, ground turmeric, ground cumin, and instant yeast.
Gradually add warm water, mixing until a soft dough forms. The dough should be slightly sticky but manageable.
Knead the dough for about 5 minutes until smooth.
Cover the bowl with a damp cloth and let the dough rise in a warm place for about 1-2 hours, or until it doubles in size.
In a large skillet, heat the vegetable oil over medium heat.
Add the finely chopped onion and sauté until translucent, about 5 minutes.
Stir in the minced garlic and cook for another minute.
Add the curry powder, ground cumin, ground turmeric, ground coriander, and cayenne pepper (if using). Cook for 1-2 minutes until fragrant.
Add the cooked chickpeas and stir to coat them with the spices.
Pour in the water and season with salt to taste.
Bring the mixture to a boil, then reduce the heat and simmer for about 15-20 minutes, or until the sauce thickens.
Mash some of the chickpeas with the back of a spoon to thicken the sauce further.
Stir in fresh cilantro if desired. Set aside.
After the dough has risen, punch it down and divide it into small balls (about the size of a golf ball).
On a lightly floured surface, roll each ball into a thin circle about 4-5 inches (10-12 cm) in diameter.
Heat vegetable oil in a deep frying pan over medium heat.
Fry each dough circle until it puffs up and is golden brown on both sides, about 1-2 minutes per side.
Remove the bara from the oil and drain on paper towels.
To assemble the doubles, place a bara on a plate.
Spoon a generous amount of channa onto the bara.
Top with tamarind sauce, hot pepper sauce, cucumber chutney, and mango chutney as desired.
Place another bara on top to form a sandwich.
Enjoy your meal!