This recipe is adapted from Martha Stewart's method of making gluten-free oatmeal cookies. Instead of using 5 different flours, she makes fresh flour out of the GF oats that are already being used for the cookies by pulsing half of it in a food processor.
Preheat oven to 350 degrees. Line two baking sheets with parchment paper.
In a small food processor, pulse 1 1/4 cups oats until very fine.
In a large bowl, cream the butter and sugars until fluffy and well-combined. Add the egg and vanilla and beat until smooth. Stir in the oat flour, oats, cornstarch, baking powder, and salt until just incorporated. Fold in the raisins, chocolate chips, or cranberries.
Drop the cookie dough onto the prepared sheets, 1 tablespoon at a time, spaced 2-inches apart. Bake until golden brown, about 15 minutes. Cool on the sheets for 5 minutes, until set.
Recipe Notes
You can mix and match your add-ins. I love just plain raisin. If making with chocolate chips, omit the cinnamon.