Grease and flour a cake pan for the cake batter.

Separate the 6 eggs. Beat the egg whites until stiff with 1/4 cup sugar (60 grams). In a separate bowl, beat the yolks with 1/3 cup sugar (65 grams) until pale and creamy. Add the lemon zest, ground raw almonds, and the flour. Gently fold in the beaten egg whites.

Make the syrup and let it cool.

For the almond yolk filling: Make a syrup with 1/4 cup water (60 ml) and 1 1/3 cups sugar (285 grams) plus a few drops of lemon juice, cooking over low heat and stirring gently. After a while, remove from heat and let cool slightly. Add the egg yolks and cook gently over a double boiler (so the yolks don't curdle), stirring slowly. When ready, add the toasted, chopped almonds off the heat.

For the Italian meringue: Prepare the syrup, brushing down the sides of the pan with water as it cooks to prevent crystallization, until it reaches 245°F (118°C). (If you don't have a thermometer, test by blowing through a slotted spoon—the syrup should form soap-like bubbles.)

Meanwhile, beat the egg whites on high speed. When stiff, add the sugar and check with your fingers to make sure the sugar is dissolved.

Using a piping bag, cover the cake with the meringue and toast it with a kitchen torch. (If you refrigerate the cake without toasting and torch it just before serving, it will be even better.)