Strictly speaking the name is reversed: it really means
肉夹于馍 (meat wedged inside the bread), with
于 dropped as Old Chinese remnant — a quirk grammarians love to point out. The dish itself comes from Shaanxi
关中 cuisine, with
腊汁肉夹馍 (Xi'an pork) and
老潼关肉夹馍 (Tongguan style, crisper bread) as the two main lineages.
