Step 1

To prepare the magic cake , start by melting the butter in a saucepan 1 . Be careful not to let it darken and, once melted, pour it into a bowl and let it cool to room temperature. Then separate the egg whites from the yolks 2 and pour the yolks at room temperature into a bowl, where you will add the sugar 3 .

Step 2

Now with an electric mixer, beat the yolks with sugar for at least 10 minutes, until the mixture becomes clear and frothy 4 . Still beating, add a tablespoon of very cold water 5 and a tablespoon of vanilla extract 6 to the yolks with sugar.  If you do not have an electric mixer, or if you prefer, you can use an egg beater or whisk .

Step 3

Add a pinch of salt 7 and the melted butter that you cooled 8 , then continue to beat for a few minutes. Sift the flour, add it to the mixture, a little at a time, and mix until completely absorbed 9 ; in the meantime, heat the milk in a saucepan.

Step 4

Once hot, pour it into the mixture 10 and let it mix for about 1 minute. It is essential that the mixture has no lumps, if it does, you can strain the mixture with a narrow mesh strainer using the back of a spoon to remove the lumps. At this point take the egg whites at room temperature and pour them into a clean bowl, start whipping them with a perfectly clean electric beater 11 . While whipping and when the egg whites have become clear: add the lemon juice (or white wine vinegar) 12 which will give stability to the mixture. You'll need very soft peaks.

Step 5

Gently beat the egg whites until stiff, so as not to make them droop 13 and mix until a fairly liquid mixture is obtained. Butter a square baking pan measuring 8x8" (20x20 cm) and 2.5" (6 cm) high 14 and line both the bottom and the edges with baking paper 15 .  The size of the baking pan is important to obtain the correct thickness of the cake.

Step 6

Then pour the mixture into the buttered and lined baking pan 16 and bake in a static oven preheated to 300° F (150° C) for about 80 minutes, until the surface of the vanilla   magic cake is golden brown 17 ; take the cake out of the oven and let it cool completely at room temperature, then cover it with a layer of plastic wrap 18 and let it set in the fridge for at least 2 hours.

Step 7

When the cake has set, remove the baking paper 19 from the baking pan and cut the cake into cubes 20 . To make cutting easier, use a long, smooth-bladed knife wet with water or use a nylon thread. Place the cubes on a serving plate, sprinkle them with powdered sugar 21 and your vanilla magic cake will be ready to be served and enjoyed!