Prepare the Oven and Pan: Preheat your oven to 325°F (160°C). Grease and line an 8x8-inch baking pan with parchment paper for easy removal.

Whip the Egg Whites: In a clean bowl, beat the egg whites with an electric mixer until stiff peaks form. Set aside.

Mix the Wet Ingredients: In a separate large bowl, whisk together the egg yolks, sugar, and vanilla extract until pale and creamy. Gradually add the melted butter and mix until fully combined.

Incorporate the Flour and Milk: Sift the flour into the egg yolk mixture and gently mix. Slowly add the lukewarm milk while whisking to create a smooth, thin batter.

Fold in the Egg Whites: Gently fold the whipped egg whites into the batter in three additions. The mixture will be lumpy, but that’s normal—this creates the magic layers.

Pour and Bake: Pour the batter into the prepared pan and smooth the top. Bake for 50–60 minutes, or until the top is golden brown and the cake jiggles slightly in the center.

Cool and Chill: Allow the cake to cool to room temperature, then refrigerate for at least 2 hours to fully set the layers.

Serve: Dust with powdered sugar before slicing into squares. Enjoy the magic of three distinct layers in every bite!