Gluten-Free Hazelnut Shortbread

I made these cookies for a friend who is gluten-intolerant. The recipe is from Martha Stewart Holiday Cookies magazine. Very tasty.

You'll need:
6 tablespoons softened unsalted butter
1/2 cup packed light-brown sugar
1/2 vanilla bean, halved lengthwise and seed scraped
(save pod for another use)
1 cup brown-rice flour
1 cup blanched hazelnuts, finely ground
1/2 teaspoon coarse salt

Preheat oven to 350F. Line an 8-inch square baking pan with parchment paper leaving a 2-inch overhang on sides.
Beat butter, brown sugar and vanilla seed with a mixer on medium-high speed until fluffy, about 3-4 minutes. Reduce speed to low; add flour, nuts and salt. Press mixture evenly into pan and chill 30 minutes.
Using the tip of wooden skewer, pierce dough all over at 1/4-inch intervals. With a knife, score shortbread into sixteen 4-by-i-inch bars. Bake, rotating pan halfway through, until golden, 30 minutes. Let cool 15 minutes. Use parchment to lift shortbread from pan. Let cool slightly on a wire rack. Cut into bars along scored lines and let cool completely.
Pretty yummy. My gluten-intolerant friend loved them!