Preheat your oven to 325°F and grab a 10-inch ungreased tube pan (yes, ungreased is important — the batter needs to cling to the sides). Sift together your cake flour and 3/4 cup of the sugar, then set it aside. You're basically creating the dry mixture that'll fold into your egg whites in just a minute, so don't skip the sifting step or you'll get lumps.

In a large bowl, beat your 5 egg whites with the cream of tartar until you see soft peaks forming — this usually takes about 3-4 minutes with an electric mixer. You'll know it's ready when you lift the beaters and the peaks kinda flop over at the top. This is the foundation of your summer fruit angel food cake recipe, so don't rush it.

Gradually add the remaining 3/4 cup sugar to the egg whites while beating continuously for another 2-3 minutes. The mixture should look glossy and thick now, and you'll have stiff peaks that stand straight up when you lift the beaters. This is honestly the most satisfying part of the whole process — it looks like whipped cream but better.

Add your vanilla extract and mix it in gently with just 2-3 turns of the mixer. Now comes the fold: sprinkle about 1/4 of your flour mixture over the egg whites and fold it in using a spatula with a gentle J-motion. Repeat this three more times, always folding gently so you don't deflate all those beautiful air bubbles you just created.

Pour the batter into your tube pan and smooth the top with a spatula — it should look like fluffy clouds in a pan. Bake for 35-40 minutes until the top is golden and springs back when you gently touch it. Don't panic if it looks a little pale — that's actually perfect, because you want it light colored.

Once it comes out of the oven, here's my secret trick that nobody talks about: immediately turn the pan upside down onto a wine bottle or cooling rack so the cake hangs while it cools completely (about 2 hours). This keeps the cake airy and prevents it from collapsing. I learned this the hard way after my first batch deflated like a sad balloon.

While the cake cools, toss your berries with the powdered sugar, lemon juice, and cornstarch in a bowl. Let them sit for 15-20 minutes so they get all juicy and syrupy — this maceration step is what transforms plain berries into topping gold. Run a thin knife around the edges to loosen the cake, invert it onto a plate, then pile those berries on top right before serving.