Naan is a leavened, tandoor-baked flatbread, a North Indian staple of refined flour, yogurt and yeast baked in a clay oven until it puffs and takes charred spots. Within a sandwich catalog its role is structural: it is one of the most widely used carriers for fillings and wraps, a soft, pliable, slightly chewy base that folds around grilled meat and vegetables without cracking. The angle is that combination of leavening and live fire, the yeast and yogurt giving lift and tang, the tandoor giving char and a thin crisp skin over a soft interior, which is what makes it both good to eat alone and good to wrap.
The build is dough then fire. Refined wheat flour, maida, is worked with yogurt, a little yeast, and water into a soft, slack dough and left to prove until it relaxes and rises. A portion is pulled and stretched by hand into a teardrop or oval, sometimes brushed with water on one face so it sticks, then slapped directly onto the searing inner wall of a tandoor. In a minute or two it balloons, blisters, and chars in spots; it is hooked off and usually brushed with butter or ghee. Good execution shows in a naan that is puffed and soft with a pliable chew and distinct dark blistering, a contrast of a thin crisp char against a tender, slightly tangy crumb. Sloppy versions are flat and dense from a tired dough, pale and bready from an under-hot oven, or dry and stiff so they tear instead of folding, the last especially damaging when the bread has to act as a wrap.
Variation is wide. The plain version stays a side or scoop for gravied dishes; brushed with garlic and coriander it becomes garlic naan; layered with butter it turns flakier as butter naan; stuffed before baking with spiced potato, paneer, or minced meat it becomes a filled bread in its own right. As a sandwich base it is folded or rolled around tikka, seekh kebab, or vegetables with onion and chutney into a naan wrap or kathi-style roll, where its softness and slight stretch let it close around a filling cleanly. The grilled-meat-filled paratha roll built on a different, unleavened bread deserves its own article rather than being crowded in here. What defines naan is exactly that pairing of a yeasted, yogurt-enriched dough with the heat of a clay oven: a bread sturdy enough to wrap, soft enough to tear, and good enough to eat with nothing on it at all.