Making real tasting cookies with only vital wheat flour? How is that possible?

Hello all, I have recently tried some cookies that use vital wheat gluten flour only, no other kind of flour, and they use erythritol instead of real sugar. Yet somehow, the cookie taste and has the exact texture of a real cookie. To summarize the ingredients on the label: vital wheat flour, erythritol, egg, butter, baking powder, baking soda, water, vanilla extract. I would be skeptical about hidden ingredients, but I don't want to jump to that conclusion. How do you think they managed to get the texture and taste of a real cookie? They use approx 10 grams of butter per cookie and under 10 grams of erythritol. Is there some kind of special technique? submitted by /u/wre232