Combining the dry ingredients: Whisk together the flour mix, oat flour, psyllium, baking powder, baking soda, and salt. Set aside.
Creaming the butter and sugar: Put the butter into the bowl of a stand mixer. Whirl it at medium speed until the butter is spread out in the bowl. Add the white and brown sugar. When the sugars are fully combined with the butter and make a creamy butter substance, stop the stand mixer.
Finishing the dough: With the stand mixer running, add the eggs, one at a time. Pour in the vanilla extract.
Pour about 1/4 of the dry mixture into the dough, with the stand mixer running. When the flour has fully disappeared into the batter, add more. Continue this until all the dry ingredients are mixed into the wet ingredients.
Add the oats, pistachios, and dried cherries to the bowl. When they are fully incorporated into the dough, turn off the stand mixer.
Scrape the dough into a large bowl and cover with plastic wrap. Refrigerate for at least 2 hours before baking. (It's best to let the dough refrigerate overnight.)
Baking the cookies: Heat the oven to 375 degrees F. Lay a piece of parchment paper down on a baking sheet.
Using a small ice cream scoop, scoop out a ball of dough. (If you do not have an ice cream scoop, make a ball of dough about the size of a ping-pong ball.) Put six balls of dough, evenly spaced, onto the prepared baking sheet. Slide the baking sheet into the oven.
Bake until the cookies are crisp at the edges but still a bit soft in the center, 12 to 15 minutes. Take the cookies out while they are still soft to the touch. Let them cool on the baking sheet for at least 20 minutes before moving them carefully to a cooling rack.
Repeat with the remaining cookie dough. Or, you can wrap the dough in plastic and store it in the refrigerator. You can make a batch of warm cookies when you want.
Variations: If you cannot eat dairy, you can make this with "buttery" sticks made for vegans. If you cannot eat nuts, don't use the pistachios!
Suggestions: If you bake by weight, you can substitute any of the last ingredients, depending on your food preferences. We like chocolate chips, raisins, walnuts, or dried cranberries in these cookies too.
Recipe courtesy of Shauna James Ahern, from glutenfreegirl.com