Preheat your oven to 325°F and grab an ungreased 9-inch round cake pan (seriously, don't grease it — the batter needs the sides to climb up). Sift together the cake flour, baking powder, and salt in a bowl. Set that mixture aside because you'll fold it in gently later and we don't want any lumps hiding.

In a large mixing bowl, combine your egg whites, cream of tartar, and the vanilla extract. Beat on medium speed for about 2 minutes until the mixture gets foamy and pale. Gradually add 1 cup of the granulated sugar (not the reserved 1/2 cup) while beating continuously.

Keep beating until stiff, glossy peaks form — this takes about 6-8 minutes total and you'll know it's right when you lift the beaters and the peaks stand straight up. Don't panic if it seems like forever; my mixer always takes longer than I expect. The texture should look like cloud-soft meringue at this point.

Gently fold the flour mixture into the egg whites in three additions, using a rubber spatula and folding from bottom to top. This is where patience pays off — overmixing breaks down those air bubbles you just worked hard to create. After the final fold, drizzle in the melted butter and fold it in carefully.

Pour the batter into your ungreased pan and smooth the top gently. Bake for 35-40 minutes until the top turns golden brown and a toothpick inserted comes out clean. The cake should smell amazing and feel springy when you tap it lightly.

Let the angel food cake berries cozy cool completely in the pan on a wire rack (at least 2 hours). I usually bake mine in the morning and let it sit all day — the texture gets even better. Once cooled, run a thin knife around the edges and turn it out onto a serving plate.

While the cake cools, toss your fresh berries with the powdered sugar, lemon zest, and water in a small bowl. Let them sit so the juices release slightly. These become your topping and sauce rolled into one.