Yes, and it is very easy. I do it all the time.
You only need a very simple calculation. You don't even have to be precise.
If you do want precision, you will have to find out 1) how much of your flour protein is gluten, 2) how much of your "vital wheat gluten" is gluten, and 3) how much gluten content you need for your recipe. Then use a simple rule-of-three calculation to get the amount needed to add.
I usually don't bother, because 1) and 2) is information which is very hard to find, and due to the large difference in gluten weight and complete weight, imprecision from not using true proportions is minimal. What I do is:
- Look up the protein content of your flour (usually printed on the package), for example 9.6 grams per 100 grams
- Look up the gluten content needed for your bread recipe. If it is not specified, 12.5% is usual for bread flour.
- Add the difference in vital wheat gluten. In the example above, add 2.9 g of vital wheat gluten per 100 g of flour.
This doesn't produce exactly 12.5% gluten content, but I think that it is within the tolerance of most recipes; indeed, not all commercial flours are exactly 12.5%, they vary with brand and season.
I add the powder to the flour and mix it well before making the bread. If I am using a preferment, I add all the gluten to the preferment and make the non-fermenting part with AP flour only, so my gluten can benefit from longer autolysis.
I have no direct comparison with "true" bread flour, as I have never used it. But my breads requiring bread flour turn out good for my standards. There is no problem with bad distribution, the dough turns out very smooth and evenly elastic. There is a pronounced difference to using AP flour only.
The summary would be that there is a larger variety of flour (measured by gluten content) in the US than in Europe.
SAJ14SAJ described the gluten categories of American flour, although exact figures for the category limits are hard to pin down. Peter Reinhart says
cake flour has 6 to 7 percent gluten, pastry flour has 7.5 to 9.5 percent gluten, all-purpose flour has 9.5 to 11.5 percent gluten, and high-gluten flour has 13.5 to (rare but possible) 16 percent gluten.
(From The bread baker's apprentice, section Types of flour). I measure exactly my gluten percentages and can confirm that these are good for recipes of the respective categories.
These flours are all made from the same flour grade, with about 50% of the grain removed and only the soft center used for fine bread. The difference comes from the grain type used, hard spring wheat (high in gluten) or soft winter wheat (low in gluten). In Europe, where only soft winter wheat is grown, all the flour is in the 9-11% range. But mills will sometimes enrich certain types of flour with added gluten, or by blending with imported flour, or by milling more of the bran (wholer flour always has more protein) in order to make some specialized high-gluten flours, e.g. Italian pizza flour. These flours are, aside from whole wheat flour, not widely available to home bakers.
I can well imagine that a European trying to bake a European recipe with American bread flour will get bad results. But if they get the AP flour, there will be no problem in the gluten.
There are many other properties of flour which differ, beyond the gluten content. But recipes are never so sensitive to them that they'd fail. If you can't tell the difference between two brands of flour in your home country, then you won't be able to tell the difference between flour with the same gluten content from the other continent either, if both are unbleached and of the same grade (= amount of bran included and particle size).
All in all, this claim sounds like an unfounded emotionally-loaded attack. It is possible that the person who made it indeed failed because of gluten content, because they didn't know that they should be buying AP and not bread flour. Or that it failed for another reason and they were looking for a scapegoat, and garbled some half-remembered knowledge (by the way, while the American wheat is genetically different, the gluten level difference was achieved centuries ago by selective breeding) to excuse their failure.
Best Answer
The author of this recipe probably happens to keep in his pantry (or more professionally speaking, dry store) just those two types of flour, and so has specified a mix to get a mid-level flour with moderate protein levels, tailored to his preferences. Given that the author is Jacques Torres, this is almost certainly a scaled down translation of a professional recipe, where that is not an uncommon practice (the very odd measurements support the idea of scaling and rounding; the weird flour measurements are probably the closest volume equivalent to a weight based scaled recipe).
Two commercial varieties (all purpose, and the less common pastry flour) also have protein levels in between cake flour and bread flour, with pastry flour being somewhere between cake flour and all purpose, typically.
If you happen to have all purpose (and you almost certainly do) I would suggest using it in the recipe for the total of both specialty flours. Very few cookie recipes are so fussy that it will actually matter very much.