I use the creaming method with electric mixer. I bought oat flour (did not make it). I’ve tried adding egg yolk and sifting. I don’t want anyone to tell that I’m not using regular flour by the texture. I use room temperature butter. I put in frig more than hour sometimes overnight. Bake 350, 10 minutes in convection oven. Is there anything I can do to make cookie soft in middle? Today bought Ultra Fine Sugar. I have not tried it yet.