This recipe was my Daughter Sarah’s favorite cake for her birthday. I tried to make it gluten free for years and each attempt came out a disaster. The problem? I was using too much Xanthan gum! Use the cake flour recipe on the Flours page for this recipe.
Preheat Oven to 350 degrees
Cream together: 1/2 cup butter or Earth Balance Soy Free Margarine, 1 and 2/3 cup sugar. As always with this step…you can’t over-mix!
Measure and set aside: 2 and 1/2 cups GF Cake Flour + 2 Tablespoons of Arrow Root or Potato Starch
Add: 1 1/2 teaspoon vanilla to 1 1/4 cup of cold water
Alternate water and flour: Slowly stir in flour about 1/2 cup at a time alternating with stirring in the water. Scrape the sides of the bowl frequently. I go about medium speed on my mixer for this.
In a separate bowl whip: Beat 4 egg white on high until they get frothy. Then add 2 teaspoons of baking powder 1/2 teaspoon at a time. Beat on high until the whites form soft peaks.
Fold in: Fold in Egg whites into the batter. Go slow with this step. I use a spatula and gently scoop from the bottom of the bowl and lift the batter over the whites…eventually it is all batter.
Bake: Timing largely depends on size and your oven. I made cupcakes today and baked them for 33 minutes. For a sheet cake I would probably go for about 40 minutes. Keep your eyes on the cake and check with a toothpick to make sure it comes out clean. 
Julie Bakes Gluten Free 