Preheat and Prep

Preheat your oven to 325°F (160°C).

Grease and line a 9×9-inch baking pan with parchment paper, ensuring the paper overhangs slightly for easy removal after baking.

Beat Egg Yolks and Sugar

In a large bowl, whisk together the egg yolks and granulated sugar until pale and creamy—about 2–3 minutes.

This step adds air and helps achieve a light sponge top.

Mix in Lemon, Butter, and Vanilla

Add the lemon zest, fresh lemon juice, melted butter, and vanilla extract to the sugar-yolk mixture.

Stir until completely blended and smooth.

Add Flour and Salt

In a separate bowl, whisk together the flour and salt.

Gradually sift the dry ingredients into the wet mixture, stirring constantly to prevent lumps.

Incorporate Milk

Slowly pour in the room-temperature milk, whisking until the batter becomes thin and smooth.

Don’t worry—the thin consistency is normal and key for the layered custard effect.

Whip Egg Whites

In a clean bowl, beat the egg whites until stiff peaks form (tips stand straight when the whisk is lifted).

Gently fold the whipped whites into the lemon batter, adding them in 3–4 portions.

Be patient and use a gentle folding motion to keep as much air in the mixture as possible.

Bake

Pour the airy batter into the prepared pan. Smooth the top with a spatula.

Bake for 40–45 minutes, or until the top is golden and the center is slightly jiggly.

The custard layer will firm up as the cake cools.

Cool and Garnish

Let the cake cool completely in the pan.

Once cooled, remove it using the parchment overhang.

Dust the top with powdered sugar for an elegant finish, slice, and serve.