What is the effect that cooked sieved egg yolks added to pastry dough will have on the final product?
I have seen some blogs (without any references) that some old European recipes utilise hard boiled eggs, for Cakes &amp; Sablé.  It is mentioned that it is used to reduce the gluten binding together too much.  I would guess it works similarly to gnocchi, the quantity of mashed potato mixed in the flour reduces the gluten leaving a soft pillowy texture.