Preheat your oven to 350°F (175°C) and prepare your baking dish by lining the bottom with parchment paper and lightly coating the sides with cooking spray.

Separate the egg whites from the yolks. Beat the egg whites until stiff peaks form, about 3-4 minutes.

In a separate bowl, combine egg yolks with granulated sugar and beat until pale yellow and creamy, about 2-3 minutes.

Add melted butter and vanilla extract to the egg yolk mixture and mix until fully combined.

Gradually sift in the flour, followed by the lemon juice and zest. Mix gently until just combined.

Slowly pour in the milk while stirring to create a smooth, pourable batter.

Fold the stiff egg whites into the batter gently to maintain airiness.

Pour the batter into the baking dish and bake for 40-60 minutes, checking for doneness after 35 minutes.

Once baked, let the cake cool completely in the pan before dusting with powdered sugar and serving.