Preheat your oven to 350 F (180 C).
Whisk together the flour, baking powder, and salt.
While the eggs are cold, separate them.
Place the egg yolks in a large bowl, add ¼ cup sugar and beat on high speed until the mixture is thick. Stir in the vanilla extract and water. Set aside while you beat the egg whites.
Place the egg whites and cream of tartar into the bowl of your stand mixer (with the whisk attachment). Whip on medium speed until foamy, about 1 minute. Gradually add the remaining sugar and continue beating until the egg whites are shiny and form stiff peaks.
Fold in about 1/3 of the flour mixture into the egg yolks.
Next, add the egg yolk mixture and the remaining flour into the egg whites, folding just until incorporated. Do not over mix the batter or it will deflate. Transfer the batter into the pan (ungreased), smoothing the top with a spatula.
Bake in the preheated oven for 30-32 minutes or until a toothpick inserted into the center comes out clean.
Remove from the oven. Allow the cake to cool down completely before removing it from the pan. Decorate the cake with icing and sugar-coated berries.