Line a 9 inch square metal pan with nonstick foil.
Combine the all-purpose flour, rice flour, sugar and ginger in a large mixing bowl.
Gently melt the butter in a microwave- safe glass measuring cup using 50% power.
Mix the vanilla with the melted butter and let it cool for about five minutes.
Add the butter to the flour mixture and stir with a wooden spoon until blended. Transfer mixture to the pan and pat it down flat. Put it in the refrigerator for 30 minutes or until cold.
Preheat oven to 350ºF.
Sprinkle top of shortbread with sugar. Place in the oven and bake for about 30 minutes or until middle appears set and edges are lightly browned.
Using a 4 pronged fork or whatever fork you feel like using, poke holes in the warm shortbread. Poke them at intervals and plan on cutting around them.
Using a razor blade or sharp knife, score the shortbread gently into 32 fingers (or whatever size you want). Do not lift it from the pan at this point.
Let sit until completely cool, then lift from pan. Use a knife to cut through the areas you lightly scored.
Store in a tin. These stay fresh for weeks.