Separate the eggs, mix the egg whites with a pinch of salt, add the sugar gradually, mix until they become hard foam.
Add the yolks, the 4 lg of cold water and mix from the bottom up.
Preheat the oven to 180 degrees.
At the end, gradually add the flour with the baking powder and mix very well from the bottom up.
Grease a tray with butter, line it with paper, pour the composition and add it in the oven heated to 180 degrees for. 35 40 min.
We do not open the oven door in the first 15 minutes, we do the toothpick test.
Mix the starch, sugar and cocoa with a few lbs of milk, mix well with a whisk. Boil the rest of the milk.
When the milk starts to boil, add the mixture, stirring constantly so that lumps do not form.
When it starts to thicken, turn off the heat and let it cool.
Add the butter mixed with the powdered sugar, the ground walnuts and the rum essence over the cold cream.
We put a saucepan on the fire, we add the sugar, we let it caramelize then we put water, we wait for all the sugar to melt and we stop the fire, we add the essence.
Cut the top into 3 equal layers, syrup in turn and put a layer of cream.
I garnished it with whipped cream and ground walnuts.