Onion Kulcha is the Punjabi leavened flatbread stuffed with a spiced onion filling, baked or griddled until blistered and served torn open and slathered with butter. The angle is the stuffing. A plain kulcha is a soft white flour bread; the onion version turns it into a filled pocket, so each piece carries a layer of sharp, spiced, slightly sweet onion sealed inside the dough rather than a bread eaten with something on the side. It sits squarely in the rich, refined-flour register of North Indian breads, more indulgent than an everyday roti and built to stand up to a heavy gravy.
The build starts with a soft maida dough, leavened and rested until slack and stretchy. The filling is finely chopped onion squeezed of excess moisture and mixed with green chili, coriander, and a dry spice line of amchur, cumin, salt and chili powder; getting the water out of the onion is the quiet, decisive step. A ball of dough is flattened, a mound of the onion mixture sealed inside, and the stuffed ball gently rolled out, slowly and with light pressure so the filling spreads evenly without bursting through. It is traditionally slapped onto the wall of a tandoor and pulled when it puffs and chars in spots, or cooked on a heavy tawa and pressed until both sides blister. It comes off brushed with butter or ghee, sometimes finished with coriander and nigella seeds pressed into the top. Good execution gives a bread that is soft and slightly chewy with a thin charred crust, a continuous layer of seasoned onion inside, and no raw flour taste. Sloppy execution is a filling that blew out so the onion scorched on the tawa and the bread is hollow, or a dough rolled too thick so the center is doughy, or onion that wept and steamed the inside into a gummy paste.
Variation is mostly about pairing and the spice mix. Amritsari versions tend to be richer, generously buttered, and served with chole and a raw onion-and-chili side. Some cooks lean the filling toward more green chili and herbs; others keep it plain and let the butter and the accompanying gravy carry it. The wider family of stuffed griddle breads, the potato paratha and its many cousins, deserves its own article rather than being crowded in here, since the paratha uses an unleavened dough and behaves differently on the heat. Onion Kulcha is judged on whether the onion is genuinely sealed inside as a discrete spiced layer, cooked through but still with some bite, with a soft buttery bread around it that hasn't gone raw or hollow.