Dark Chocolate Walnut Blondies

Bahan-bahan (12 porsi)

• ½ cup melted butter
• 1 cup light brown sugar
• 1 egg
• 2 teaspoons vanilla
• 1 cup all-purpose flour*
• ¼ teaspoon kosher salt
• ½ teaspoon cinnamon
• ⅔ cup dark chocolate chips
• ½ cup walnuts, chopped
• ⅔ cup brown rice flour
• ¼ cup tapioca starch
• 3 tablespoons potato starch