2¾ - 3 Cups GF Flour:
1¼ Cup GF Potato Starch
1 Cup GF Oat Flour* (or GF Sorghum Flour)
½ Cup GF Corn Flour* (or GF Rice Flour)
¼ Cup GF Tapioca Starch
1½ tsp. Guar Gum
½ - ⅝ tsp. Xanthan Gum
⅝ Cup (½ Cup + 2 Tbsp.) Sugar
1 Cup Unsalted Butter; softened and cut into 1 inch pieces (*or ⅞ Cup Crisco)
1 Tbsp. Water (*or 3 Tbsp. Water if using Crisco)
½ tsp. Vanilla Extract (optional)
¼ tsp. Almond Extract (optional)
Preheat oven to 300°. Cover 1 or 2 baking sheets with parchment paper and set aside.
Measure GF Flour ingredients into a large bowl, sift ingredients together then re-measure ingredients to 2¾ Cups Total; save excess flour for future use. Add Guar Gum, Xanthan Gum, and Sugar; sift mixture two to three times.
Add softened Butter pieces, water, and extracts to the dry GF mixture. Knead mixture with your hands until a soft pliable dough forms. Divide the dough in half. Pat or roll each half of dough into a 6 inch circle that is between ¼ and ½ of an inch thick. Place each round of dough on top of the parchment covered baking sheet. Sprinkle the top of each round of dough with sugar (optional).
Bake shortbread at 300° for 30 minutes. After baking for 30 minutes (or until dough is set but still soft) remove from oven and slice with a pizza cutter into thin wedges (do not separate the wedges!). Then return the shortbread to the oven and continue to bake for an additional 10 to 15 minutes or the edges have begun to brown. Leaving the shortbread on their baking sheets remove from oven and cool on a wire rack. Once the shortbread has cooled break into wedges and serve or store.
If using Crisco instead of butter then substitute ⅞ cup of Crisco for the 1 cup of Butter also use 3 Tbsp. of Water instead of 1 Tbsp. of Water.