We had to sample A LOT of these cookies before we finally figured it out, but once we did that, we cracked the code and came up with a copycat version that’s just about indistinguishable from the original. So what’s that secret ingredient? It’s old-fashioned oats! Before you get carried away, no, these aren’t oatmeal cookies. The oats, a scant 1/2 cup, are ground up into oat flour and used to supplement the all-purpose flour already in the dough. This lends a subtle, yet distinct flavor that makes these cookies so special.