Preheat and Prepare: Preheat your oven to 150°C (130°C fan). Line a large baking tray with parchment paper. This is important as it prevents the cloud bread from sticking.

Create the Yolk and Cheese Base: In a medium bowl, combine the egg yolks, cottage cheese, granulated sugar, vanilla extract, lemon zest (if using), and salt. Use an immersion blender or a small food processor to blend the mixture until it's completely smooth and creamy. Set this aside.

Whip the Egg Whites: In a separate, scrupulously clean, large bowl, add the four egg whites and the cream of tartar. Using a stand mixer with a whisk attachment or a hand mixer, beat the egg whites on medium-high speed.

Reach Stiff Peaks: Continue beating for 4-5 minutes, or until the egg whites have formed stiff, glossy peaks. You'll know they're ready when you can lift the whisk out and the peak holds its shape without flopping over. For a deep dive into this technique, BBC Good Food has a great visual guide.

Gently Fold the Mixtures: Take about a third of the whipped egg whites and fold them into the egg yolk mixture to lighten it up. Then, gently fold in the remaining egg whites in two more additions. Be careful not to overmix; you want to keep as much air in the batter as possible. Stop when you see just a few streaks of white remaining.

Fold in the Blueberries: Gently fold the fresh blueberries into the batter. I find it's best to do this in just a few strokes to avoid crushing them and streaking the batter with purple.

Shape and Bake: Spoon eight equal mounds of the batter onto your prepared baking tray, leaving a bit of space between each one as they will spread slightly. They should look like little clouds.

Bake to Golden: Bake for 22-25 minutes, until they are a beautiful golden brown colour and feel firm to the touch. They will have puffed up nicely in the oven.

Cool Completely: Let the cloud breads cool on the baking tray for a few minutes before carefully transferring them to a wire rack to cool completely. They will deflate slightly as they cool, which is completely normal.