When making a gluten-free recipe, it is important to use the same brand of gluten-free flour as the recipe indicates, as each brand will behave differently. In this recipe, I call for King Arthur’s brand. Don’t be tempted to use another brand unless you know how to alter the other ingredients.

Preheat oven to 350 degrees and spray two cookie sheets with cooking spray and line with parchment paper. The spray will help the paper stick to the pan and make dropping the cookie dough onto the pan easier.

Melt butter completely in a medium saucepan on low heat and add the chocolate, stirring frequently until it is ¾ of the way melted. Remove it from heat then allow the mixture to sit as the chocolate continues to melt. Stir it occasionally until it is smooth, then set aside to cool slightly.

While the chocolate is melting, beat the eggs, sugar, vanilla, baking powder and salt on high speed for a full 5–6 minutes, until the batter is thick, creamy and completely smooth. It’s very important to set a timer and not rush this step.

Stop the mixer, pull back the head and add the melted chocolate, water and coffee. Use your spatula to combine ingredients. Return mixer head to bowl and turn setting to medium-low. Mix the ingredients until thoroughly combined, scraping the sides of the bowl several times.

In a small bowl, whisk together flours, xanthan gum and cocoa powder until well blended then add mixture to the batter and stir just until incorporated. Then scrape the sides down and again and fold in walnuts.

Cover and chill the dough for at least 30 minutes in the refrigerator. It will appear runny, but don’t worry. The dough will firm up in the fridge.

Form the cookies by dropping 2 Tbsp dough onto the parchment paper about 2" apart. (Using a small ice cream scoop really helps with this job!) Bake cookies 12–14 minutes, rotating and swapping baking sheets halfway through.

The cookies are done when the center is set but not firm. If you want chewy cookies, remove them from the oven, slide the parchment onto a wire cooling rack immediately and allow them to cool. If you like a crispier cookie, leave the cookies on the pan to cool. Enjoy!