Preheat oven to 375 degrees. Line an 8 x 8 inch cake pan with parchment paper and allow the paper to hang over the sides slightly. This will make it easier to lift the brownies once they are baked
In a large mixer bowl sift or whisk together the dry ingredients until fully combined and no lumps are in the dry ingredients
Add the eggs. Beat on low 10 seconds to incorporate the eggs. Increase speed to medium-low and beat for 30 seconds or until all the dry ingredients are moistened. This can also be mixed by hand if you do not want to use a mixer
Scrape down the sides of the bowl. Add the butter. Beat on low 10 seconds to break up the butter. Increase speed to medium and beat 30 seconds or until fully combined
Scrape down the sides of the bowl again. Add the vanilla and coffee. Beat on low 10 seconds to incorporate. Increase speed to medium and beat another 30 seconds or until fully combined and a creamy batter has formed
Scrape down the sides of the bowl and push the batter to the center of the bowl. Allow the batter to sit uncovered at room temperature about 5 minutes to absorb excess moisture and allow xanthan gum to bind ingredients
Scoop batter into prepared cake pan and spread the batter evenly throughout the cake pan. Make sure the top is smooth
Place in preheated oven. Bake at 375 degrees 25-28 minutes or until a tester comes out clean
Remove from the oven. This will be soft but will firm up as it cools. Allow to cool in the pan about 1 hour or until mostly room temperature and the brownies are firm enough to remove from the pan
Grasp the parchment paper handles. Gently lift the brownie slab out and transfer to a wire rack allow to cool completely before slicing or frosting. Store leftovers in an airtight container at room temperature for 1 week. If frosting the brownies store in an airtight container in the refrigerator up to 1 week