It is likely that it was originally created by combining mussels, a popular and cheap foodstuff eaten around the Flemish coast, and fried potatoes which were commonly eaten around the country in winter. Although Belgium claims to be the birthplace of french fries, their origin is uncertain. The way in which the mussels are cooked can vary significantly, but probably the most common recipe is Moules marinière, which use white wine, shallots, parsley and butter to cook the mussels.
Within Belgium, bintje potatoes are preferred as a basis to make fries because of their high starch content. They are generally double-fried (fried, left to cool and then fried again) in order to make them both moist in the core and crispy on the outside. The moules and the frites are served on separate plates so that the fries don't become moist. Often, the moules are served in the same pan used to cook them. One of the 1150 original Belgium beers accompanies perfectly this dish.
About the stamp
The stamp, issued on October 28, 2013, is part of a definitive series depicting King Philippe.
Moules-frites - Wikipedia
Sent from Antwerp (Antwerp / Belgium), on 21.12.2015