Preheat your oven to 400°F. Grease the wells of a 24-cup miniature muffin tin thoroughly with cooking oil spray.
In a large bowl, place the flour blend, xanthan gum, cornstarch, salt, baking powder, baking soda, and granulated sugar, and whisk to combine well.
Add the brown sugar and whisk to combine, working out any lumps in the brown sugar.
Create a well in the center of the dry ingredients, and place the butter, eggs, and vanilla, mixing to combine after each addition. At the end, mix well until the batter appears thick and glossy.
Add the chocolate chips, and mix until the chips are evenly distributed throughout the dough.
Fill the wells of the prepared muffin tin fully with the batter. If your muffin wells are on the larger side and your batter doesn't fill them all, leave some empty of batter and fill halfway with water to ensure even baking.
Place the tin in the center of the preheated oven and bake for 5 minutes. Reduce the oven temperature to 350°F.
Continue to bake until the blondies are puffed and golden brown, and a toothpick inserted in the center comes out clean (about 12 minutes more).
Remove the tin from the oven and allow to cool in the baking sheet for 10 minutes before transferring to a wire rack to cool completely.
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Notes
Originally published on the blog in 2014. In 2022, more photos, video, and more text resources added; recipe simplified slightly.