In a medium bowl sift together the rice flour, salt and spelt flour. Set aside.
In the bowl of a stand mixer or in a large bowl with a hand beater, beat the butter until creamy then add the vanilla extract and beat until combined. Add the sifted icing sugar and golden brown sugar and beat until combined. Gradually add the sifted flour and salt and beat on low until the dough comes together. Finish mixing the dough by hand until completely incorporated. Form the dough into a ball and wrap in plastic wrap. Chill it in the fridge for a minimum of 2 hours up to 24 hours.
Preheat the oven to 350 degrees F and line two baking sheets with parchment paper. Roll the dough out to ¼ inch thick, cut shapes with a cookie cutter and place 2 inches apart on the baking sheets. Bake for 9 minutes or until bottoms are golden brown. Transfer cookies to cooling racks and allow to cool completely. Store in air tight containers.