Separate the egg yolks from the whites and let them come to room temperature for about 30 minutes.

In a large mixing bowl, combine egg yolks and sugar, and beat on medium speed for 2-3 minutes until pale and creamy.

Add melted butter and vanilla extract to the yolk mixture, then fold in the flour gently.

Incorporate lemon juice and zest, then gradually stir in the milk.

Beat egg whites in a clean bowl until stiff peaks form, then gently fold into the batter.

Pour the batter into a greased pan and bake in a preheated oven at 350°F (175°C) for 40-60 minutes.

Cool completely in the pan on a wire rack before serving, dust with powdered sugar.