2C (16,20 fl oz) (480 ml)whole milk, at room temperature
1/4C (2 fl oz) (60 ml)natural lime or lemon juice
2tbsplime or lemon zest
Confectioners sugar, for decorating
Instructions
Preheat the oven to 320º F (160° C). Grease and line a square baking pan of approximately 7.80 inches (20 cm) with parchment paper
Crack open the eggs and place the whites in a clean medium bowl and the yolks in a large bowl. With an electric mixer or a hand whisk, beat the egg whites for 3 minutes until they begin to form stiff peaks. Set aside until needed.
Separately, with the same electric mixer or hand whisk, beat the egg yolks with the sugar for 3-4 minutes until they become lighter in color and fluffier.
Add the melted butter and beat for 1 more minute until blended. Then add the flour (previously sifted) and beat for 30 seconds until you get a smooth and homogeneous mixture.
Continue beating the egg yolks, and in the meantime add little by little the milk with the lemon juice and zest. Beat for 30 seconds more until all ingredients are incorporated.
Using a rubber spatula fold in the beaten egg whites in three separate additions, doing folding motions very carefully so as not to lower the whipped egg whites.
Once the batter is ready, pour it into the pan and even it out with the spatula so that it covers the entire surface. Bake the cake for 40 minutes to 1 hour or until the top is lightly browned and the cake is firm to the touch. The baking time can vary greatly depending on the oven, so keep checking the cake.
Once the cake is ready, take it out of the oven, let it rest for 20 minutes inside the pan and then turn it out and let it cool for at least another 10 minutes. Decorate the cake with powdered sugar, cut it into 9 equal squares and it is ready.