Place the nuts into a food processor and pulse until pecans are about pea size. Then use the on switch until pecans are sandy (over processing will make the flour sticky, so be careful).
This is perfect for gluten-free recipes or to substitute in existing recipe ideas where you want to cut back on wheat. Just a reminder this product, like all nut and seeds flours, will not rise.
Related Recipe: Chef Hernandez' Polvorones (Mexican Wedding Cookies)