• Preheat the oven to 350º F. Empty 1 cup of all purpose flour, properly measured, into a medium bowl. Remove 2 tbsp of flour and return to the flour bag. Add 2 tbsp of cornstarch to the flour. Sift 5 times. In this step you’re really making you own cake flour, so everything needs to be incorporated and light as a cloud.
  1 cup minus 2 Tbsp (105g) all purpose flour, 2 Tbsp cornstarch
• Add in 3/4 cup sugar and salt to the flour mixture. Sift 2 more times. Set aside.
  1 1/2 cups (297g) granulated sugar, 1/4 tsp salt
• In a mixing bowl over medium speed, begin to beat the room temperature egg whites for about 2 minutes. Add in the cream of tartar, vanilla extract and lemon zest. Continue to beat the mixture for 2-3 minutes, turning the speed up to medium-high. 
  12 large egg whites, 1 1/2 tsp cream of tartar, 1/2 tsp vanilla extract, 2 Tbsp lemon zest
• Gradually add in the remaining 3/4 cup of sugar, about 1 tablespoon at a time. Wait 10-15 seconds between scoops of sugar. Continue to beat the mixture on high until stiff peaks form. The mixture will be white, glossy and really airy! The whole beating process can take 10-13 minutes. 
• Remove the bowl from the stand mixer. Gradually sift in the flour mixture (in about 3-4 batches). To do this hold the sifter over the bowl, and add in 1/3 or 1/4 of flour mixture. Then use a spatula to gently FOLD the mixture together. To your best to not over mix, which will deflate your egg whites. 
• Add half of the angel food cake batter to an un-greased angel food cake pan. Then drop in half of blueberries, one at a time. You can use a toothpick to push some of the blueberries into the batter. 
  3/4 cup (105g) blueberries
• Add the remaining batter to the pan, and add in the remaining blueberries, pushing some down into the batter again.
• Place in the oven to bake for 40-43 minutes or until a popsicle stick or kabob skewer comes out clean when inserted into the cake. 
• Once the cake is done baking, immediately invert the pan. I like to stick the center of my angel food cake pan on a mug or can of beans to cool inverted. Allow the cake to cool for 2-3 hours, then use a small spatula or knife and go around the sides of the pan and the center piece to help release the cake from the pan. 
• Place the cake on a serving plate. 

Lemon Glaze

• Using the lemons you zested, squeeze out the juice. Combine 3 tablespoons of lemon juice with 2 cups powdered sugar. Stir with a spatula until well combined. Drizzle the glaze over the cake. Garnish with lemon slices, blueberries and baby’s breath. 
  3 Tbsp fresh lemon juice, 2 cups (227g) powdered sugar, Additional lemon slices
• If serving the next day, place the unglazed cake in an airtight container on the counter. Add the glaze a few hours before serving.