Step 1

Preheat the oven to 325°F (160°C). Grease a 8 x 8 inch baking dish, or line it with parchment paper.

Step 2

Separate eggs, and beat the egg whites in a medium-sized bowl until they become stiff. Set aside.

Step 3

Beat the yolks with the sugar until light and fluffy. Add butter, vanilla extract, and continue beating for one or two minutes.

Step 4

Pour the flour, and mix until well incorporated.

Step 5

Add lemon juice and zest, then slowly start adding the milk, and beat until everything is well mixed together.

Step 6

Add the egg whites, one third at a time, and gently fold them using a spatula. Repeat until egg whites are folded in, but there should be still white bits of egg whites floating in the batter.

Step 7

Pour the batter into the prepared baking dish and bake for about 50 minutes, or until the top is lightly golden and the cake is firm to the touch. The baking time could vary depending on the oven, so take a peek around 45-50 minutes and see how it looks.

Step 8

Let cool completely and sprinkle some icing sugar on top.