Step 1

Preheat oven to 325F. Line 8×8-inch baking dish with parchment paper leaving overhang the sides, lightly grease with cooking spray, set aside.

Step 2

Separate the egg whites and yolks.

Step 3

Beat the egg whites until stiff peaks, set aside.

Step 4

Beat the egg yolks with sugar until pale in color.

Step 5

Add melted butter and vanilla and mix until well combined.

Step 6

Now add all purpose flour and mix until fully incorporated.

Step 7

Add lemon juice and lemon zest and mix.

Step 8

Slowly add milk until fully combined.

Step 9

Gently add the beaten egg whites into the mixture and whisk by hand. Don't worry if there are small lumps of egg whites left in the mixture. These lumps will create the top layer of the cake during baking.

Step 10

Pour the batter in the prepared pan(batter will be very thin and lumpy)

Step 11

Bake for 40-60 minutes or until the center is barely jiggly and the top is firm to the touch. Start checking the cake after 35 minutes as baking time may vary depending on your oven or pan. Do not over bake the cake as this will cause it to become rubbery and lose its custard layer.

Step 12

Once the cake is done, cool it completely before dusting with powdered sugar.