Tiropita - Triangle is the handheld cheese pie folded into a triangle: thin pastry wrapped around a soft cheese filling, baked or fried until the layers crisp and the inside stays molten. It is national rather than regional, sold from bakery cases and cart windows across Greece, and the triangle shape is the point. It folds the filling into a closed packet you can eat with one hand while walking, no plate, no fork, no leak if it is made right.
The build starts with the pastry. Thin sheets of dough are brushed with oil or butter and layered, then a band of cheese filling, usually feta loosened with egg and sometimes a softer fresh cheese to keep it from going dry, is laid along one edge. The strip is folded corner over corner, the way a flag is folded, so each turn traps a pocket of filling inside another wall of pastry. Good execution shows in the layers: the pastry shatters in distinct leaves, the filling is salty and slightly tangy and holds together instead of running out the open corner, and the bottom is cooked through rather than pale and raw under a browned top. Sloppy work shows up as a soggy base where filling soaked the dough before it set, a triangle so thinly filled it is mostly air and crust, or an over-floured seam that stays doughy in the middle. The triangle should be crisp at the edges and yielding at the center, and the seal should hold to the last bite.
The triangle is one cut of a much larger family. The same filling baked in a coiled rope or a full sheet tray, the spiral and pan versions, behaves differently because the pastry-to-filling ratio changes and the spiral keeps more of its interior soft. Swapping the cheese shifts it again: a sharper aged cheese in the mix pushes it savory and firm, while a milder blend reads creamier and rounder. There is also the spinach-filled cousin built on the identical pastry technique, which deserves its own article rather than being crowded in here. What stays constant in the triangle is the format: a sealed, portable wedge meant to be handed over warm and eaten on the move.