Begin by preheating your oven to 350 degrees F (175 degrees C). This will give your cake enough time to warm up while you're mixing your ingredients.
Next, it's time to sift the dry ingredients. Combine the rice flour, powdered sugar, and xanthan gum in a sieve and sift them 3 times to ensure a smooth and airy cake.
In a large glass, metal, or ceramic bowl, beat the egg whites on high speed until they start to get foamy. As they become more fluffy, add the cream of tartar and salt. Keep beating until stiff peaks form. Then mix in the white sugar and vanilla extract.
Now, it's time to combine the egg whites and the flour mixture. Dollop some egg whites into a large, flat bowl, then sprinkle some flour mixture on top. Continue to layer the egg whites and flour mixture, then gently fold them together.
Spoon the batter into a 2-part angel food cake pan. Make sure to pour it evenly so that the cake bakes evenly.
Bake the cake in the oven until the top is golden brown and a knife comes out clean when inserted in the center. This will take between 50 and 60 minutes. Remove the cake from the oven and let it rest for no more than 5 minutes. Then, immediately flip it upside down and rest it on a wine bottle until completely cool, which will take between 1 and 2 hours.
Once the cake has cooled, turn it over and run a knife around the edge if needed to loosen. Then, flip it over onto a cake stand and remove it from the pan. Your angel food cake is now ready to be served and enjoyed!
