In Hungary, they sell "rétesliszt", strudel-flour. What makes it better for strudel? Is it higher gluten? Lower? Softer? Harder? Which flour in a typical (USA) supermarket comes closest to rétesliszt?
I know from experience that all-purpose flour sucks for making strudel dough, and for that reason I usually just buy the frozen fillo (phyllo) stuff, but it's really not the same thing at all – it's too paper-thin and the sheets are too small. In a pinch, puff pastry rolled out real thin can also work, but the result will be a very German-style strudel.
Best Answer
Your best bet is a stone ground bread flour or hard flour in the US that means finding a local mill. At your standard supermarket a high protein bread flour is your only option if you can find it there. I generally have to venture out to a Whole Foods market to find that as my "local" grocery store doesn't carry it. You could also try Tipo 00, I have run across it in some specialty stores. You are looking for the highest gluten content you can find so that you can get the elasticity you need to make proper strudel.