Start by separating the egg whites into a large bowl, making sure no yolk gets in. Beat on medium speed until foamy, then add the cream of tartar. Continue to beat on high until stiff peaks form. The egg whites should stand tall when you lift the beaters. This will give the cake its light, fluffy texture.

Slowly add the gluten-free powdered sugar, one tablespoon at a time, while continuing to beat. The mixture should be glossy and hold stiff peaks, ensuring your cake is airy.

Sift the gluten-free flour blend over the egg whites, folding it in gently with a spatula to maintain the fluffiness. Add the vanilla extract and fold that in as well. Be careful not to deflate the egg whites as you mix.

Pour the batter into an ungreased tube pan. Don’t grease the pan, as the cake needs to cling to the sides to rise properly. Spread the batter evenly across the pan.

Place the pan in a preheated 350°F (175°C) oven and bake for 35-40 minutes, or until the cake is golden on top and a toothpick inserted comes out clean.

Once baked, remove the cake from the oven and invert the pan onto a cooling rack. This prevents the cake from collapsing as it cools and helps it retain its height. Let it cool completely.

Once the cake has cooled, carefully run a knife around the edges and remove it from the pan. Top with whipped cream, fresh blueberries, and sliced strawberries. Serve immediately for the best texture and flavor.