Onglet : now that's good beef: 'onglet' in French, or 'fat crow' in Flemish, or ‘hanger steak’ in English. 
This delicious piece of meat is also sometimes called the 'butcher's steak' : real butchers who cut the meat themselves often keep it for themselves. 
Inspiration recipe can be found here: https://www.meattheworld.be/nl/recepten/gebakken-longhaas-met-sjalottensaus-onglet-l-echalote.

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Meat the World attaches great importance to the origin of its meat, most of which is Belgian. It is carefully grown on its own farm and known as : 'Lokers grassland meat'. And the price... it is surprisingly low! You will even pay less than in the average supermarket. The quality is superior. You can taste it from the first bite of a tender piece of chicken, an aromatic strip of steak or a tender cutlet.