Preheat the Oven:

• Preheat your oven to 325°F (160°C). Grease an 8×8-inch baking dish and line it with parchment paper for easy removal.

Separate the Eggs:

• In a clean bowl, separate the egg whites from the yolks. Beat the egg whites with an electric mixer until stiff peaks form. Set aside.

Prepare the Batter:

• In a large mixing bowl, whisk the egg yolks, sugar, and vanilla extract until light and creamy.
• Add the melted butter, lemon zest, and lemon juice, mixing until combined.
• Gradually add the flour and salt, mixing until smooth.

Incorporate Milk:

• Slowly add the warmed milk to the batter, whisking continuously to ensure a smooth mixture. The batter will be very thin—this is normal.

Fold in the Egg Whites:

• Gently fold the beaten egg whites into the batter in batches. It’s okay if some lumps remain; this helps create the layers.

Bake the Cake:

• Pour the batter into the prepared baking dish and bake for 50-60 minutes, or until the top is golden and the cake is set. The middle may still jiggle slightly, which is fine.

Cool and Serve:

• Let the cake cool completely in the pan. Once cool, dust with powdered sugar, slice, and garnish with fresh lemon slices or zest if desired.