How to Make It
Preheat oven to 350°.
Weigh or lightly spoon flours and potato starch into dry measuring cups; level with a knife. Combine flours, potato starch, baking powder, xanthan gum, and salt in a medium bowl; stir with a whisk.
Combine brown sugar, melted butter, and oil in a medium bowl; stir with a whisk until blended. Add vanilla and eggs, stirring with whisk until blended. Gradually add flour mixture, stirring until blended. Fold in minichips, brickle chips, and pecans.
Pour batter into an 8-inch square metal baking pan coated with cooking spray. Bake at 350° for 20 minutes or until a wooden pick inserted in center comes out clean. Cool completely in pan on a wire rack.