GF non-stick cooking spray
1 1/4 cup white rice flour
1/2 cup sweet rice flour (substituted corn starch)
1/4 cup cornstarch
1 tsp baking soda
1/2 tsp salt
3/4 cup butter or margarine softened
1/4 cup granulated sugar
1 cup packed brown sugar
2 tsp vanilla
3 large eggs
1 12-oz bag semi-sweet chocolate chips
Preheat oven to 350°F. Grease a 9 x 13-inch baking pan with cooking spray.
Whisk together dry ingredients.
Cream butter, sugars, and vanilla together until blended, 30-45 seconds. Use medium-high speed on handheld and stand mixers. The butter will look like a grainy paste. Add eggs, 1 at a time, mixing well between each addition. Add dry ingredients and blend until a dough forms. Use medium speed on a handheld mixer, medium-low on a stand mixer. Using a wooden spoon, stir in chocolate chips.
Spread dough evenly into prepared pan. Bake 45 min or until a tester comes out clean. Remove from oven and cool on wire rack. Cut into 12 squares.