Ingredients

1 ½ cups egg whites, at room temperature

1 ½ teaspoons cream of tartar

1 ½ cups granulated sugar, divided

1 cup cake flour

1/4 teaspoon salt

1 tablespoon fresh lemon zest

1 teaspoon vanilla extract (or lemon extract)

1 cup fresh blueberries

1 tablespoon all-purpose flour (for coating blueberries)

Instructions

Step 1: Preheat your oven to 350°F (175°C). Prepare an ungreased 10-inch tube pan. Do not grease the pan to allow the cake to climb and rise properly.

Step 2: Sift together the cake flour, ½ cup of granulated sugar, and salt at least 3-4 times. Set aside.

Step 3: In a very clean, grease-free large bowl, beat the room temperature egg whites on medium speed until foamy.

Step 4: Add the cream of tartar to the foamy egg whites and increase the mixer speed to medium-high. Continue beating until soft peaks form.

Step 5: Gradually add the remaining 1 cup of sugar, 1-2 tablespoons at a time, beating until firm, glossy peaks form. Fold in the lemon zest and vanilla extract gently.

Step 6: Carefully fold one-third of the sifted flour mixture into the egg whites using a gentle upward motion. Repeat with the remaining flour in two additions, avoiding overmixing.

Step 7: Toss the blueberries with 1 tablespoon of all-purpose flour to coat. Then gently fold them into the batter.

Step 8: Spoon the batter evenly into the ungreased tube pan. Run a knife through the batter to remove large air pockets.

Step 9: Bake for 35-45 minutes until the cake is golden brown, springs back when touched, and a skewer comes out clean.

Step 10: Immediately invert the pan and cool for 1 ½ to 2 hours upside down to prevent collapsing.

Step 11: Once cool, run a knife around the sides and center tube, invert onto a plate, slice with a serrated knife, and serve.

Tips & Variations

Use room temperature egg whites for maximum volume; if needed, warm cold whites in a warm water bath for 10-15 minutes.

Coat blueberries with flour to keep them suspended in the batter rather than sinking to the bottom.

Substitute cake flour by mixing 1 cup all-purpose flour minus 2 tablespoons plus 2 tablespoons cornstarch sifted together.

Try different citrus zests like lime or orange for a unique flavor twist.

A lemon glaze or fresh whipped cream with extra berries makes a beautiful accompaniment.

Storage

Store the cooled cake in an airtight container or tightly wrapped with plastic wrap at room temperature for 2-3 days to keep it moist and fresh. If your cake has a glaze or extra fresh fruit toppings, refrigerate it well-covered to prevent drying and odor absorption. When refrigerated, bring to room temperature before serving for best texture.

FAQs

Can I use frozen blueberries instead of fresh?

Fresh blueberries are preferred because frozen berries release excess moisture that can weigh down the delicate batter. If you must use frozen, toss them in flour while still frozen and gently fold them in, but be prepared for a slightly denser cake.

Why do I need to cool the cake upside down?

Cooling upside down prevents the delicate angel food cake from collapsing as it cools. This method supports the cake’s structure while it sets, preserving its height and airy texture.