I have never known what it is in English, it is the diaphragm muscle, which is why it is expensive because you only get one on a beast. So delicious. Hanger steak, eh? Goodness never heard of it in English.
I don’t think it is hard to cook, I heat up my cast iron grill until it is smoking hot then put my oiled & salted bit of meat on it about 40 seconds a side, pepper it as it goes onto a plate and that is it.
I think that is American English rather than English English… 
So what is it called in British English? Ah I looked it up and in the UK they call it onglet. This indicates to me that in the UK people don’t generally eat it and the rumour about butchers keeping it for themselves may well be true 
I think you’ll find it’s “skirt”, not to be confused with what the Americans call “skirt”…
" The hanger steak is becoming more popular in Europe. In Britain it is called a “skirt steak”, not to be confused with the American skirt steak. In French it is known as the onglet , in Italian the lombatello , in Dutch the longhaas , in Polish the świeca wołowa , and in Spanish the solomillo de pulmón or entraña or entécula "
I thought skirt was hampe? Ugh so confusing. Didn’t have this problem when I lived in GB as I just pointed out the bits I wanted and my lovely butcher cut them off the carcase, most of the time the cuts aren’t the same as here.
Here I know what to ask for by name obviously. My lovely alas now-retired butcher here was a brilliznt cook as well as a brilliant butcher so a positive mine of useful information. His wife’s pot au feu en salade was in my children’s top 3 favourite goûters.
When I see the onglet raw, I recognize it as skirt… a very cheap, tasty cut…
Happy memories, as ideal for newly married folk with little money… just needed long, low cooking and turned out delicious. If not cooked long enough… tough as old boots.
I am fairly sure skirt is hampe Stella, much cheaper than onglet. Oh! Maybe hampe is flank? I think there is a confusion between the two as they are close to each other and look quite similar. Hampe is much cheaper and thinner than onglet.
I am sorry to say this but I really believe that long slow cooking for onglet is a criminal waste of it when it is so delicious and tender flashgrilled. I cook tough bits like jarret long and slow, or oxcheek, but never onglet or hampe or bavette etc.
But each to each, obv.
We casseroled skirt. If onglet is skirt then that explains why I’ve never ordered it again after eating it as a tough steak in Chartier.
You cant get better than skirt for long slow cooking.
How was it cooked to be tough? I can’t imagine tough onglet (unlike eg faux filet or rumpsteak which can be tough as old boots even if not overcooked)
Onglet is so lovely and bloody 
Barely eatable, Vero. Almost uncuttable I think practically all of it was left.
Similar experience with bavette…I think I’ve only had one eatable one in my life.
It’s not hard to cook, as long as you know what you’re doing. If you overcook it, as many might do, then its ruined.
God how awful and unlucky, those are both such delicious succulent (yes i know a bit disgusting that word) cuts in fact just thinking about them makes one slobber and grow fangs - proper meat. Mmmmmmmmmm
Yes, skirt is hampe.
I think there might well be some confusion… since traditional English butchery (my era) certainly used to be very, very different from French and even American butchery…
Thus, simple translations don’t necessarily work…
but who cares… the mist is rising out of the valleys… and the sun is shining… 
Where’s that, its UK now
Don’t forget shin.
That is what I use for long slow cooking - it gets so tender and the juice is velvety. So delicious. Lovely for making daube or peposo or Viêt style stew.
Jarret is shin, I think. There’s possibly less scope for variation on that bit of the beast. Oh queue de boeuf (oxtail) is good too 
Warning; humourless reply follows.
The way this post thread has developed is a good example of how the human race is not facing up to the need to do things to prevent it’s demise. A serious & interesting article was shown at the start, which would have made sense to anyone &, even if they had no clue beforehand, at least should have made them consider reducing their consumption of animals & animal products.
Sadly the thread has been hijacked & turned into an orgy of meat loving. I find this very depressing.