Mi Xian store signboard

Quick answer：

Mi Xian, also spelled as Mee Siam or rice noodles, is a popular Chinese dish, especially in the Southwestern regions. A 'store signboard' refers to the sign outside a shop that indicates its business. In the context of a Mi Xian store, the signboard would typically display the name of the shop and the type of dish offered, in this case, Mi Xian noodles.