Preheat the oven to 350°F. Spray a 10" tube pan with nonstick cooking spray. Set aside.
Sift the flour, ¾ cup of granulated sugar, and cocoa powder into a bowl using a fine mesh strainer.
Whisk it together and set it aside.
Add 11 egg whites to a large bowl.
Beat the eggs until they're foamy, about 1 minute.
Add in the lemon juice, baking powder, vanilla and salt. Beat for 2 minutes, or until soft peaks start to form.
Next, add the last ½ cup of granulated sugar, but only add 2 Tbsp at a time, mixing before adding more. Stiff peaks will start to form once all sugar is mixed in.
Add half of the dry flour mixture to the egg whites. Gently fold them in with a spatula.
Once mixed, add the last half of the flour mixture.
Gently mix until completely combined.
Pour the batter into the tube pan. Run the spatula through the batter to help eliminate any air pockets. Give the pan three taps on the counter to remove some more. Smooth the top if needed.
Bake for 40-45 minutes or until a toothpick comes out clean when poked through the center. The cake should spring back when lightly pressed. Let cool for 10 minutes.
Run a butter knife along sides of the pan and inside tube. Gently invert the pan to flip the cake onto a rack to cool completely.
Make Whipped Cream (Optional):
Add the whipping cream (heavy cream), sugar and vanilla extract to a medium bowl. Use a hand mixer to beat until soft peaks start to form. This will take 5-10 minutes (mine took 9 minutes).
Serve a slice of cake with a big dollop of whipped cream and fresh berries. Enjoy!
Make sure to use room temperature egg whites. You can separate them from the egg yolks and let them sit for 45 minutes on the counter before mixing. Or add eggs to a bowl of warm water (not hot) for 15 minutes.
Do not use egg carton egg whites for this recipe. I’ve tried it and the results aren’t nearly as good! Using 11 fresh eggs is definitely worth it.
Set a timer on your phone while using a hand mixer. This will ensure you’re mixing for long enough to get the best cake results.
To help the cake release from the pan, run a knife along the edges or use a spatula.
Leftover cake can be stored in an airtight container in the fridge or on the counter up to 3-4 days.